Nick and Amelia get several hours to run around the apartment every day. Their pen area is very large, and some nights they decide to not come out at all. Other days, they are out for as long as they are allowed.
Tobi's pen is a good size, and she gets time to come out and run around in the hallway 2-3 times a week, for several hours at a time. I feel bad that she doesn't get more time out, but she has quite a bit of space in her pen and 3-level condo, plus she gets pets every time someone walks by her pen.