Is there anything specific that you should look for when buying a used kayak? Is it like a car, where there are certain things you want to check before you make that purchase?
If nobody has had problems with ones they have bought second hand, what's the first thing you've noticed that needed attention on your own kayaks, obviously other then the routine scuffing of the bottom.
If it isn't rotomolded, the seams...once they start to go, the kayak is near death.
Screws, if any. Make sure they are sealed...water tight. Hobie is very guilty of not sealing all screws.
Seat upgrade. You spend hours in an uncomfortable seat...getting that upgrade makes it much easier to fish longer.
Protect your rubber seals. Silicone will help protect it. I use Trident Silicone Grease. It's for SCUBA gear, but I've been using it on my kayaks, and pretty much any other rubber that gets exposed to water and sun, for years.
A paddle that fits you and your kayak. If your kayak comes with one, and your of an average build, that paddle will probably do. But, if you're really tall, or really short, that paddle might not work great for you. Gotta find the one that suits you and your yak.
Foot braces. Some are cheaply made....fall out...break...or just bend and don't really offer you any support. Make sure your yak has decent foot braces/rests.
That's all I've got for now.
Ben nailed it!
only thing I'd add would be a test drive