I work in utility construction in the mountains and spend a good chunk of my time hiking through tough terrain and brush/forests and I have some Patagonia jackets that have held up remarkably well through snags and tears/etc, add onto that their lifetime warranty and I feel like it meets the spirit of BIFL (in that I only have to buy it once and it will last me for life or get replaced for free).

That being said, I use "buy it for life" as more of a "this is the highest quality product in a given category". Sometimes that really does mean heirloom items (nice knifes/cookware/watches/etc) and sometimes it means that it's a high quality product that will possibly be heirloom quality, but If not the company will take care of you (darn tough/Patagonia/peak design/Popov leather/Mitchell leather/ etc).