depends on how much you use the aircon, and how big the condo, as march can be a little hotter, also how much that charge you per kw, not all charge the government rate.
covid extension are another entire conversation lol. If you have been out of Thailand since you covid extension, then I would suggest you look at a multi entry visa from you home country. Depending on you plans. Merry Christmas
that would be up to immigration, technically 2 by land and I believe by air as many as U desire, until immigration say sorry U are not a tourist.and to get correct visa and denies you entry.