I’d go with my Buffalo as well.. it’s 15 years old and now has a hole in the chest pocket but I still love it.
Just (last year) bought the Teclite model and that’s my go to jacket now, I’ve worn it running, biking and more often that not all weekend. It’s a lot cooler than the Mountain shirt which means I should be able to wear it more 😉
I’ve got some Outdoor Designs gaiters which I’ve had for 10+ years. Bought when I was in an MRT and still use them in the winter.. they’ve had a hard life and still perform brilliantly.
I’d also say my Arcteryx Merino beanie as well.. that’s worn week in week out throughout the year and is about 8 years old.. still brilliant 🙂
My biking kit is more transient, I guess it’s more susceptible to fashion, but I’ve got some Sidi Dragon MTB shoes which are about 7 years old that are now out of retirement for use on the CX bike