Although scores are valid for 5 years, generally you sohuld not use your scores if they are older than say 3 years. I dont think you need to resend the scores. Schools will keep your scores even if you dont apply for that particular season.
i dont see why you wouldnt use the score even if it is 4 years old. its not like all of a sudden you become dumb. 5 years is the limit, and you shouldnt feel bad about getting the most of it. i dont see why adcoms would care, the score goes into their average just the same whether you took it 1 years ago or a week ago.