If I have the choice, I stay out in the woods and happens occasionally (10-20%).

#1) Reality in my household is that I have a 2 1/2 year old spark plug running around the house, so I need to relieve Mama from her duties once in a while.
#2) Oh yeah - I own a small manufacturing business and have "some" responsibilities to my customers and employee's.
#3) I have had little luck with rain or stiff winds, so I opt to use my hunting time wisely (see #1).
#4) Sometimes I get bored after 3 or 4 hours.
#5) Sometimes my back and neck start killing me enough to make me think I might lose my faculties.
That's a good sign to leave, when the pain make's you think you might tip out of your tree stand.