Dan Warren wrote:

I had the tank pumped out back in 85 then didn't have it done again till 2
years ago. I lived alone for about 15 years. The guy who pumped said it
was in good condition. So I wouldn't worry about gettting it pumped out so
soon. Living alone, every 5-10 years should be adequate.

The answer is so heavily influence by what gets flushed, the number of people
using the system, the size of the tank and several other factors that a rule of
thumb won't work.

It's not that hard to drop a dip stick in the tank a couple of times a year...

--
"Tell me what I should do, Annie."
"Stay. Here. Forever." - Life On Mars