I have been renting a Cessna 172 and recently have a 150 availabe, at 30 bucks an hr less that the 172 I can stand some lack of comfort. At the moment, I'm about 50 lbs beyond the standard 170 lb pilot. Flying solo presents no problem but if I wanted to take another person I need to know how much fuel is in the tank so I don't go over gross wt. The plane is not always topped off after each flight so it's generally not a problem whether there is a passenger or not. I'm just flying for fun so I can adjust my flying time accordingly and to be on the safe side, I always check my fuel at each stop. It's just good practice.
Bob