I fear it will get stale before then...
I could barely watch through the last season, it already feels stale to me :/ Same problem as Lost really - once you go through everyone's history you need a strong plot which... meh.
UNlike Lost though a prison can cycle characters easily, it's just bad form to do that too heavily which leads you back to point one.
I can't imagine they'll manage 3 years with Piper she's already super annoying.
I hope Piper gets out soon as she finishes doing her time. Show how she adapts to life outside of prison and whatnot. No convoluted way to keep her in.
they will though; Panties thing will get her more time, she'll get bitter and hardened and do something else stupid and get more time. Or she'll take the fall for someone else who's sooo close to getting out that she has a bleeding heart moment true to character and get more time..