Is it a bad idea to run Snow Tires year round? I have my snow shoes on my X5 right now, they are almost new. Will the snows wear out faster, or just not grip/handle as well or what?

I was going to swap tires only (same rims), but it's gonna be near $75-$80 bucks to do that, and I'd be doing it twice a year. That vs buying some new summer rims and tires for probably $1200 or so (might be able to get my tire place to mount/unmount tires already on rims for free).

Thoughts?