When someone mentions gear, I don't think of clothing or shoes. And I'm sorry, but Fleece Jackets/pullovers are not considered lightweight.
To be honest, when I buy lightweight gear, I'm not thinking I'm going to be using it 10 years later because I'm hoping that there will be something even lighter I can replace it with. And rather then looking at age, I think its more relevant to how much use they had. Someone who owned something for a year may have used something far more than someone who owned it for 5 years.
That said, my MLD CF Grace Solo tarp is 6 years old and still going strong. As is my 5 year old MLD Superbivy. Both with 3500+miles of use with them. I have both a 7 and a 5 year old ULA backpacks (different sizes) that are in excellent shape. One used on the PCT and the other for a large chunk of the AT. I have a 15 year old down sleeping bag from Marmot that are still in excellent shape though I don't use it much anymore since its too warm for most of my hiking.
If you must talk about clothing, my 7.8oz OR Zealot paclite Gortex Jacket from 2006 was just retired last year due to a small tear. It went with me on a PDT thru-hike and a large chunk of the AT plus numerous smaller trips over the years. I think thats pretty good considering how thin the material was. I have several lightweight baselayers from Patagonia, Marmot and REI that are still going strong after many years, but you'd expect that. My lightweight Montbell down jacket from over 5 years ago are still in excellent shape even after going on the PCT and AT though its been more used as a pillow then as a jacket. Though the act of stuffing it into a stuff sack every night is probably harsher wear on it then just wearing it.
