The weather is getting cooler and many are thinking about removing their performance tires for winter / snow tires. However, what condition are your old snow tires in? Can you eke out one more season? Should you?
Keep in mind that the more tread depth the tires have, the more effective they will be in loose snow and slush. Checking your tread depth may seem pretty obvious (here's how), but there is more to this than taking a quick look at the tread. In order for winter tires to perform well in snow, they need adequate tread depth so they are "biting" into the snow instead of "nibbling" at it. Most winter / snow tires start at 10/32nds of an inch to 12/32nds of an inch. 6/32nds of an inch is the minimum tread depth that Tire Rack recommends for winter driving.
Check out "What Honest Abe Doesn't Tell You About Minimum Tread Depths" for more information about tread depths for winter and all other seasons, too.
If you find that your old snow tires have less than 6/32nds of an inch of tread depth, they are ready to be replaced. There are many great winter / snow tires available, but a good starting point would be to check out Bridgestone's Blizzak line. If you're looking for Bridgestone tire reviews on some of the top Blizzak tires, read "Blizzak Winter / Snow Tires."
You can find the right auto tires online, when you shop by vehicle.