I agree with Texasroadlawyer. My only additional comments would be

-helmet
I've never gone without one. I've been under my quad and am really glad I had it on. I've heard many people say as long as the quad is turned on you should wear one. People have been known to flip the quad loading or unloading.

- chest waders
They're hot, but....in the past, more than once a regular boot came off, stuck in the mud.

- a hockey jersey
They come clean better than anything else & the long sleeves reduce scratches from tree branches

- sunglasses or goggles
because of dust, mud, wind and tree branches