I thought at some point I read that FHA loans don't have that? I'll look more into again in a few years when my house will appraise high enough.

Certain loans (like fha loans) have PMI for life

Is an appraisal enough or is refinancing required?

Check your loan documents, mine have often had a "if valuations go up you can pay for an appraisal when you cross 20% or it's assumed if valuations have gone up enough AND enough time has passed".

Usually it auto-expires when you pass the 20% equity mark based on original sale price.

It's easier with a local lender as opposed to someone who sold off the mortgage, of course.