Lessons: When is Enough Enough?
One interesting thing about The Process of Learning the harmonica is that there are quite a few built-in fun and musical things that, much like the man's part in The Procreation Process, can be done with minimal effort and almost no practice.
You can pick up a harmonica, diatonic or chromatic, and, within a few minutes, you can produce sounds that won't be 
terrible. And they're fun. You're actually making music!
Admittedly, this is somewhat easier on diatonic, and, judging by the trucker I heard recently at a rest stop on Highway 5, more than a few fun and fairly recognizable tunes are pretty easy to play with little practice, and a six pack of beer.
Early Onset Chromatic Harmonica players also have built-in stuff that sounds like Music, but they need to cut back on the beer and dress just a bit better.
DIATONIC ADVANTAGE
You can go to parties, and, at any time, 'quick-draw' your instrument and play some of those 12 traditional licks.
(Handy Tip: If there are other diatonic harmonica players at the party, you won't have to play, since they'll all know what you would have played, had you played, and you can all agree to just "say no", and keep stuffing the hors d'oeuvres into your pockets for your private After Party.)
CHROMATIC ADVANTAGE
You can go to parties, and watch the 'quick draw' diatonic players do Their Thing, imagining that you are above all that stuff, while simultaneously wishing you could do all that stuff, and go for the hors d'oevres before the diatonic guys get them all.
So, either way (Beginning Chromatic or Diatonic Harmonica), you have some built-in things that can make Life fun, with no need for those expensive and pesky Lessons.
EXPENSIVE AND SOMEWHAT CLASSICAL INSTRUMENTS (and Parental Lies)
Compare that to, say, early-stage Clarinet Students, whose parents can realistically expect at least a two-year time period where they will be lying to their kids when they say "Yes, honey, that really sounds great!" 
"WOW! I've never heard anyone do THAT on a clarinet before!"
In most cases, It does not. In the rest of the cases, it still doesn't, but Love trumps Reality at times like those.
The only thing built into a clarinet is a squeak.
A more honest parent, concerned about the effect that telling lies might have on the location and quality of his/her Afterlife, might try "WOW, Honey, I've never heard anyone do THAT on a clarinet!", but, from The Universe's viewpoint, I suspect it's pretty much the same. A technical lie: so, still, an error-with-penalty.
Heaven just got ten yards more distant.
The almost instant musical gratification is enough to allow a certain subset of budding harmonica players to just stop there, enjoy the music, have Great Fun, and concentrate on other things most of the time, like making a living, paying the mortgage. and Living Life. Living each day like it was only one of many yet to come, and, perhaps, singing "Tomorrow" from Annie.
All Good. If your goal has been met, that's just fine. You're having fun. And that's really cool. Good for you. (I am ashamed that I used to look down on people who stopped learning at the point of having fun, and were ambivalent as regards Getting Better, but, I realized recently, that that was a bad attitude on my part, and asked myself "who am I to say that everyone has to have Professional Level Goals?..." (that's rhetorical, question-wise, so I left it unanswered, but it made my point to me, and I agree...mostly.)
ALL of which finally leads us to make a decision:
LESSONS...are they for ME ?
FLASH!!!! One can study the harmonica the way people study Regular Instruments. This can be done on both chromatic and diatonic, domestic or imported, paper or plastic?.....but it usually isn't.
By the time I started harmonica, I was old-ish, around 58, give or take some amount of DNA-related male pattern baldness gifted to me by my father, and had been a professional musician ever since I started trying to avoid paying taxes.
Therefore, the ONLY way I could study this new instrument was the way I'd done things all along.
I couldn't set lower standards based on the Manufactures' Suggested List Price of my instrument. (See sidebar on the side)
MY way to get thru this was this:
- Start on piano, where you'll learn to see, read music, and to listen. The Basics. The "Here's Dick and Jane and Spot The Dog" kind of musical basics.
- Quit piano as soon as your parents let you quit, after all...... baseball.
- In fifth grade, see a film of Rafael Mendez and his two destined-to-be-urologists sons playing The Flight of The Bumble Bee, and Bugler's Holiday and ask the music teacher if you can get trumpet lessons.
- See the very last elementary school-supplied trumpet being given to Steve Rappaport, and believe the teacher when he says "we're out of trumpets, here's an alto sax, it's JUST THE SAME!"
- Take private lessons on alto sax and clarinet, studying first with the High School Band Director, (a trombone player) and then with symphonically-employed players, get some assorted Prizes and Medals for Performances, until you go to college and major in math, chemistry and physics, because your father was a professor and you thought your parents expected you to go into the Family Business, which you assumed they did, but they didn't.
- Wait for a war. Get your draft notice.*Want to See The World? (Go East, young man?)". Quickly enlist into the Army Music program and get 'hired' to teach at the Armed Forces School of Music, and thus not have to duck Foreign bullets in a Foreign Land.
- Add flute to your bag of instruments, fainting the first time you try it, but gradually working up to a more Professional Level degree of Air Control.
- Try to add bassoon to that bag, and quickly realize that you don't have enough thumbs.
- Successfully add oboe, and have the Correct Answer for your (first) wife's question: "Either The Oboe goes or I go. What'll it be?"
- Get divorced (see above). Move to Los Angeles, (where you'll get some of that bullet-ducking experience that you missed in the Army). Become a doubler-for-hire for TV, Film, and other musical things, at which point you look for Steve Rappaport to thank him for all the extra money you earned by playing more than one instrument, instead of just trumpet, and to ask him "So, how's that trumpet thing working out, Steve?"
- Do that for 45 years, retire when synthesizers and better players overtake anyone's need to hire you.
- Say "yes" when the Union asks if you want to take your pension.
- Say "yes" when the government asks if you want your social security.
- Say "yes" when you are playing a show and the clarinet part has notes labeled "Harmonica cues", and they ask if you play harmonica. *I said "yes", which kind of means my whole harmonica career is based on a lie.
- Call Tommy Morgan and study chromatic harmonica for ten years.
- Finally realize what fun can be had playing music for free.
Unless you're nine years old, you probably don't have time for that journey.
BUT JON, I DON'T HAVE TIME FOR THAT JOURNEY
(see, I just told you that might be the case)
So, if you want to approach the Chromatic Harmonica the way say, an average clarinet or flute student would, what do you do?
For The Basics, a local teacher of chromatic harmonica would be the best choice. Unfortunately,, due to zoning laws, and some over-zealous Home Owners' Associations, there aren't that many of those folks available. (HEY! this community is Gated for a reason!!)
That said, the main reason for the lack of Local Professional Harmonica Players/Teachers is that people feel the need to earn a living and it's not all that common to find someone able to do that as a harmonica player/teacher. If you're lucky enough to get past those barriers, and have a good local player, you can learn a lot about tone production by just sitting with a player who has tone, while you sit, listen, play, get feedback. Quite a few players do actually have an audible tone, and, if you have Options, pick one whose tone you enjoy.
NO LOCAL PLAYERS/TEACHERS ?
There are people who are said to be successful teaching using Skype. It's true.....I've heard them say it, and they sounded like the were being truthful. While it will not totally suffice to teach some esoteric things, such as tone quality, it could work in a limited way. Perhaps that's all you'd need or want. Good recording EQ can replace hours of tone practice.
TONE..DO I HAVE TO DO THOSE LONG-TONE EXERCISES LIKE I'VE HEARD CLASSICAL MUSICIANS HAVE TO DO?
YES: Yes, you need to do long tones. Very long notes. Very steady notes. Start very softly, and get louder and then get softer....until you hear your heart beat within the tone. Then, figure out how to get rid of even that sound, unless you only plan on recording stuff that's at your heart beat speed. N.B. I can't get rid of the heart beat sound, Tommy (Morgan) can....in a heartbeat...(sorry)
HOWEVER: Usually if you record a bit, you'll find that the EQ and Reverb buttons are your Friends, and can replace many hours of tone practice. However, doing a nice smooth long tone, from soft to loud, at times can be useful, and meditative, and probably won't hurt.
IF you are really interested in the Professional Approach, and don't live close to a Great Player, you can divide things up:
Have one Skype teacher for the physical bits of how to play the chromatic, and then, just go to your local Orchestra or College Music Department, and find one of their flute players, and ask for music lessons. Pick carefully. Flute players are an Interesting Bunch, and share your range.
JAZZ?
It seems that those who are accepted as great chromatic players, jazz division, mostly started on other instruments. They CAME to the harmonica after already KNOWING music.... reading, theory and so on. It was a smaller job to transfer over to the chromatic harmonica.
IF you want to learn to play jazz on Diatonic or Chromatic harmonica, I suggest you not study with a harmonica player, opting, rather, to study with a Great Jazz Player in your area. Picking a jazz piano player seems a good choice. They know stuff. Guitar players also know that stuff, but they tend to go On The Road on a whim, leaving you in The Lurch. And, no, I'm not sure what a lurch is, but apparently being left in one is a Life Negative.
That way you'll get a good education in Jazz, without suffering from whatever barriers your harmonica-playing teacher might place on HIS or HER own playing, by virtue of the Harmonica being so difficult, and try to put their barriers in YOUR mind.
One great thing about how Tommy taught me is that he NEVER said "this is difficult", and so, even at first, when I gathered with other Harmonica Owners, and played a bit, they usually asked "Hey, HOW the heck do you play that fast, clean....etc"...after just starting the instrument??
Nobody told me it was hard....for which I thank them.
A good teacher will let YOU decide what's possible and what's not. And, you'll be the one who can move "can't be done" into the "holy crap, I just DID IT ! column.
(that's fun, and yes, I'll watch my language)
IN CONCLUSION
Obviously, not everyone has those options for studying, but there's enough information above here to get you started, or daunted.... pick one.
Doing this "Professional Way" business takes time. And Practice. And isn't for Everybody.
Having fun playing music is a fun goal to have.
Perhaps you could use a Teacher.
It's up to you, I suppose.
And here's your Bonus YouTube Clip, featuring John Cleese.
