I probably said it wrong, but aren't they called tubes? If not, I'm sure you know what I mean.
When I bought my (used) bike a few months ago, the bike shop said the tires would probably last another 100 miles or so. If I haven't gone 100 miles, I'm getting close. I race a week from tomorrow. Should I get new tubes this weekend? Or is it bad to have someting like that brand spankin' new right before a race?
Do you mean tires (outside rubber that contacts the road) or tubes (inside liner that holds the air)? No reason to change your tubes unless you're losing air, no reason to change your tires unless there are visible signs of wear or damage.
You should change your air though, no reason to race with stale air.