realize it's a function of tank sizes, but how many days between emptying tanks are realistic / typical for 2 persons when "boondocking" (hookups not available)? or maybe a range? thanks!
We have 25gal black, 12 gal gray. When we're boondocking we can go a week no problem, we do not generally take showers (er, we're 50 miles from anyone else, and being dry desert sweat doesn't tend to stick around and get all that stinky anyway) and dish washing is very limited. After a week I usually take a shower to make sure there's enough water in the gray tank to flush the slinky.
As you can see there is no answer that fits everyone or every situation.