Most light aircraft, have two separate independent fuel tanks, you have a selector valve to switch between them .
Usual method, is to run off of one tank until it's at about half, then switch to the other tank, to make sure you can get fuel from it, instead of waiting until it's almost empty, then realize you can't get your remaining fuel out of the other tank .
Running out of fuel, is surprisingly not too uncommon in the general aviation community, just because someone has a pilot's license, doesn't mean they should have one .
Natural selection is quite effective in the aviation field !!!!!