As others have said, its usually best to check the requirements of the office you will be attending.
Its not usually the drama people make it out to be. I do a marriage extension in Pattaya every year, they require all the usual documents, passport, tm30 etc, Bank letter stating 400k funds for 60 days, also want a kor ror 2 (proof still married) from the local ampher . Photographs showing you and wife at your house (standing in front of the letterbox showing house number, sitting on the lounge etc, i submit the same photos every year). After submitting the documents immigration visits your house in the next couple of days, just to check you haven't hired a local bargirl to pretend to be your wife. a couple of weeks later go back to immigration and get 1 year stamp.
I literally do it all in one day, start at ampher when it opens, then to the bank, then to immi office.