A lot of posts here have given out wonderful and helpful ideas! I can’t provide any more on top of this, but I want to speak to this:

How long to grow a community

However long it takes. Some communities never take off, some communities that seem obscure will sometimes propel to popularity. However long you keep at it is 100% completely up to you! As long as you are finding some fulfilling or enjoyment out of it. You don’t owe anybody anything in this regard. If you are tired or stressed from it, there is nothing wrong with dropping the community you tried to grow. You tried to start something, and that is commendable in itself.

With that said, I enjoy geocaching every few months or so when I look into it! Unfortunately there aren’t that many caches near me. I’ll subscribe and maybe make a few caches of my own!