5-string players - do you still play 4s?

I've recently become quite enamored of my 5-string, and just want to play it all the time. Learning it was a bit of a trip, remapping the strings in my brain. Now I find when I go back to my 4, it feels very strange, and I tend to make string transposition mistakes. So some questions for 5-string players:

• Do you play 5'ers exclusively now, or do you play 5s and 4s?
• If you play both, any difficulty switching back and forth? Do you rehearse all songs on each?
• If you're '5 exclusive', did you buy an extra 5 for a backup, and will you ever play 4 again?