If you treat your gear well, it will almost all last a whole thru-hike.
Rain Jacket If you have a bad year, you can have 80+ days of rain, and the shoulder straps of your backpack will wear out (delaminate usually) the shoulders of your rain jacket.
Shoes are covered over in the other question pretty thoroughly I'd say.
Pants: If you wear pants, chances are you'll go through a couple pairs. Usually the ankles are the part that goes, followed by the knees/groin.
Socks: Depending on what type you go with, you'll go through quite a few pairs. If you think of durability when choosing socks, it could be a wise choice. Darn Tough socks are a staple for AT hikers.
Beyond that, I'll just say that a lot of your gear will be heavily worn by the AT. Putting 150 nights on all your gear is more than a lifetime for most hikers. I would say you'll end up retiring at least some of these: all your daily worn clothes, tent, backpack, all waterproof stuff sacks (will no longer be waterproof), sleeping bag, insulated jacket, and rain pants.
I've heard from various thru-hikers, and it's a pretty wide range that people experience. I know some people that have their triple crown who used essentially the same set of gear the whole way and others who changed everything after each trail. Personally, I had to replace my backpack and stuff sacks after the Pacific Crest Trail, and then I thought all my clothes were fine, but they fell apart within days of starting the Continental Divide Trail.