Keep condoms, kotexs, grease and such out of it and anything else that's not bio degradable and you may never have any issues with it.
I had to have one of mine pumped once in 30 years. And that was due to a renter flushing tampons down the toilet for several years when they were there.
My parents has had there tank in service for over 50 years. With them and three kids and I can not remember them ever having to have thiers pumped.
