There is no practical sense in creating more than one introduceyourself post. In terms of life, you only introduce yourself once to a person, so what purpose does creating multiple introduction posts serve?
I can tell you exactly what purpose it serves. Fishing for votes.
My best advice:
Don't do it. You don't want that label.
I think you are correct that between 1 and 2 should really be the maximum. Here is my reasoning for two posts:
A lot of people when they join Steemit haven't decided what their niche is going to be and who their target audience is going to be. The put out a post that tells some information about them, but doesn't really grab any readers. I know that my first Introduce yourself post was pretty pathetic.
Over time, you find your groove on Steemit and you start to become a better writer. At that point I think it is acceptable to write another re-introduce yourself post so that new users and the people that have started to follow you can really find out who you are.
I think we all make a lot of mistakes we wish we could take back when we first start out on Steemit. That's one of the downfalls of everything being written to the blockchain forever. It is encouraging though to see the evolution of users as they spend more time on Steemit and begin establishing connections.
There is no hard or enforced limit for using that tag so you can do as many as you want, however 1 should be all you need to introduce yourself properly.
If you consistently use that tag you will be making a name for yourself but probably not one that you will like. There are many established/experienced steemians that look down on those who do not use the appropriate tags, that spam in the sections with content that does not belong, etc.
I believe your initial assessment of the situation is correct, 1 is good, 2 maximum, perhaps on your first year anniversary or something, kind of like a re-introduce myself post
There really is no existing rule preventing anyone to post as many times as they want under the #introduceyourself tag but common decency dictate that, since the tag is mostly geared towards newbies and someone who didn't get much visibility on the platform yet one must at least do it at least once every 3 months.
My reasoning for this is actually pretty simple. Steem's user retention is very low, over half of the people you befriended today will most likely leave after a month or two (Sorry!) making you seek out new friends and people who share the same interest as you.
Due to how blog posts are being displayed, your new friends will most likely not take the time to scroll down on your blog and find your #introduceyourself post and is the main reason why I think one should do a "reintroduction" about theirselves and what they are upto to let those new people and new followers to catch up and got to know you better.
Well I believe that ideally you're meant to do only one and in that one you're meant to tell steemit about yourself.
I don't really see the need in doing a second introduceyourself post, it's almost like as if you're saying that we didn't hear you the first time you were introducing yourself.
You could definitely make another introduceyourself post if you're introducing g something new on steemit, like a new service or contest, I've actually seen people do this before.
Finally, I've also seen people do more than one introduceyourself, but the ones after the first one are usually just people trying to introduce someone who just joined steemit on their own blog.
I hope this helps
As far as I know there is no rule saying you can't introduce your self more than once but I am sure if an established account picks it up you may be flagged.
It just doesn't make sense to me why you would want to introduce your self more than once. Maybe they think that they can get more rewards and votes i don't know. The funniest introduce myself post I saw was a user who supposedly had just joined but used bots and spent more than $100 on it. That person knew way too much and was milking the system.
I can see someone maybe doing another one 6 months after they joined if there interests had changed maybe but no other reason.
I have a rule . I introduce myself once to a person . If I do it more than that then the other person will think you are a weirdo .why would you do it twice other than get more upvotes . And the community will cop into this fairly fast and in the long term could be detrimental