I am running some BFG sportcomp2's in the summer which crack at around -7C, so I was delaying my winter tire switch over until mid May and switching back in early September. That was wearing my snows pretty fast, so when they got down to 5/32, I bought a used set of rims with the new set of snows. So now I can save my good snow tires when I actually need them, Dec. to early March, and run the old snow set in the shoulder seasons.
You can probably get a mounted set of half worn snow tires on rims for little more than the rims would cost, then you can run good snows in the winter and get some really nice tires for the summer. My snow tire buying strategy now is to get ones that have good wet pavement grip so I can run them down to 2/32 in the shoulder seasons without being slippery in the rain.