Proper ferret areas?

[Sevaede]

What would you consider to be a proper sized ferret habitat? My parents have one that is four feet tall on one side and three feet tall on another. It's a nice bit of room and housed two ferrets quite nicely.

I would like to get a ferret habitat long before I bring home a ferret(s). I need to know what would is considered a proper sized home for one or two. Of course, they would have lots of time out of it + outside trips (on leash).

[Queen of Poop]

My large ferret cage is 3 ft x 3 ft square and 5 ft tall. The small cage, for housing a sick or recovering from surgery ferret is 2 ft x 3 ft x 3 ft tall - which might be fine for one lone ferret to live in. Ferrets are curious little guys and need room to roam and explore, otherwise they will get bored.

[iusara]

I have two cages, one huge one for the summer, and one small one for the winter. I would use the big one all year round, but it is so big that I need to clean it outside.