I thru-hiked the AT in 2010, but I didn't really use separate clothes for sleeping. Some say it's better because it's less sweaty.
The other issue is you cook while in your day clothes, then you should supposedly BEAR-BAG your clothes and sleep in other clothes.
Seriously, do people actually do this??
And my other question is, if I were to hike the PCT or CDT, should I start doing this? It seems like extra weight and bother.