While marriage visa renewal is more difficult, you don’t have to leave the country every 6 months, you only need 400,000 in a Thai bank account, but you do need proof of 40,000k baht of income coming in monthly.

I think for those coming in on cooking, medical or Muay Thai classes, they’ll probably start requiring you prove you are still engaged in those activities when you reenter the country on the visa. So that’s a cost you’ll likely have to consider down the line, in addition to travel expenses for leaving the country.