@Andy *********
you cannot just apply for a non-O visa. It has to be based on something. non-O based on retirement, non-O based on Thai spouse, non-O based on half Thai child, non-O based on parent of a foreign child studying in Thailand, non-O based on married to a foreigner working in Thailand. As I said there are at least 10 different types of non-O and they all have different requirements for extension. Without knowing what classification of non-O, this question is impossible to answer. Unless you have a crystal ball and can tell us.