I unpack simply because I don’t like living out of a suitcase. It feels like I’m still traveling rather than having arrived at a destination.
I have to admit, though, that I’m confused by the comments suggesting that keeping your clothes in a suitcase makes it easier to pack back up at the end of a trip. I just put all of my dirty clothes in a laundry bag each night and at the end of the stay I put the bag in my suitcase. Literally takes me five seconds to pack my clothes at trip’s end.
Yeah I am a bit confused too. Is the dirty laundry staying in the suitcase the whole time? I am assuming it doesn't. So then by leaving everything in the suitcase aren't you just slowly unpacking your suitcase a day at a time as you wear things and then re-packing it all back up dirty at then end, versus unpacking it all in the beginning and re-packing it all back up dirty at the end?
In my case, my wife likes to use the drawers and keep a laundry bag, not to mention she tends to overpack. All of her laundry inevitably ends up in my suitcase at the end of the trip, because of her being a shopaholic when it comes to souvenirs for our nieces and nephews. This has prompted me to organize my laundry in the recent years, just to fit double. Trying to stuff all of the laundry and Disney bags full of loot into suitcases in prior years has led to many a quarrel, LOL.
On top of that, we're always skating the thin line weight wise at airline check-in on the way back, which is always fun.