well, there is one other guy on here for sure who believes sand will basically never wear out...i don't have enough experience to make that claim as i wasn't the original owner of our house, but i do know the sand filter i have (sta-rite) is the original filter going back 20 years anyway. i've had the pool 4 years now, don't know if the sand was ever changed. i did change the sand out this year as i was renovating my entire pool equipment setup and thought now i'll know when everything "got started". i am good at backwashing regularly (at least once every 2 or 3 weeks whether i think it needs it or not) and put filter cleaner in every fall before close down. the sand i took out had a little put of clumping here and there but i'm sure would have been serviceable for another season anyway.

the fellow i'm referring to who basically believes sand can last forever has taken all his sand out, cleaned it and put it back in..your guy maybe the same type..me, i'd rather change out sand if necessary every 5 years or more if i have it out anyway.

i'm not using sand anymore by the way.i've become a big believer in zeobrite since i put it in in july.