I definetely switch my bags on a daily basis! I can't go out if I don't match (Even if it's just going to get something from the car!) lol!
I think thats why i'm always about 2 hours late to meet people all the time! lol!
At the same time though I don't use my nice bags (the ones that cost $2000+ or the ones that are more delicate) in the rain or when i'm doing something that may potentially harm my bag such as going clubbling, etc.
Now its winter here and its raining a lot! So i'm using my LV hampstead PM a lot, its kind of became my rain bag since then!