I've been using the same Pyrotect driving shoes from the Lemons "slightly better everything" kit for over 6 years. 24 races total including A&Ds, although the usage has varied between races (from the snowed-out race at ECR to the last full-24 with multiple stints in two cars). Both shoes and the tongue-mounted SFI tags are still in very good shape, and I'm not very strict about removing them before I go walking around the paddock either. The tread is just now starting to wear out on the soles beneath the balls of my feet.
Probably depends on the manufacturer, because my gloves are a different story. I lost one of the cheap Pyrotect gloves from my kit a few years ago and bought a new pair of RaceQuip gloves that actually looked a little nicer. After maybe three years, the SFI tags have faded to the point you can barely read them, and one is coming off from a failing seam. At Barber I noticed one finger is starting to show some wear. I'll be buying new gloves soon, probably not from RaceQuip.
Command Pilot/Flight Director, Escape Velocity Racing
Index of Effluency, Heroic Fix, Class C Trophy, now hopelessly gunning for Class B.
Currently 1-2 vs. Team Fairlylame in the Class of 1964 Championships