Repairing kokatat socks

I have the kokotat gore-tex bibs that are ~4 years old. The socks have been patched once after year 2 (should have been every year since it gets worn or there are holes). After the 4th year, I send it in for service again and they can't patch the socks, but can replace them for $175.

What's the best way to repair worn out sections in the socks and I'm just curious if other drysuits have this problem? 

You can repair dry socks with Aquaseal or Marine Goop.  If the hole is small, you can just put a thin drop of Aquaseal over the hole.  Put a piece of wax paper or scotch tape inside the sock behind the hole so you don't accidentally glue the sock to itself.  If the hole is larger, buy a small piece of thin ripstop nylon at a fabric store and glue it over the hole.  You should be able to extend the life of your drysocks for many years with this kind of repairs.  Keep the repairs thin so they don't create a lump in the dry sock.

But you should figure out why you are getting holes in your dry socks.  I have dry suits which I have used extensively for years without getting holes in the dry socks, but you developed holes after only two years.  What kind of footgear are you wearing, and is it abrading holes in your socks?  I use wet suit booties, which don't have any hard points which could abrade dry socks.

A tip about Aquaseal:  If you open a tube of Aquaseal and use a small amount of it, after a month or so the top of the tube will harden, and the only way to use the bottom of the tube is by cutting off a corner of the tube.  Which is irritating, because Aquaseal ain't cheap.  To avoid this problem, after you open a tube of Aquaseal, keep it in your freezer.  You'll need to defrost the tube before you use it again, but freezing the tube will prevent the Aquaseal from hardening.  Marine Goop doesn't have this problem.

Great tip on the Aquaseal.

Thanks for the tips and I'll give it a try. I fish a lot when I can so there are a lot of hours on them over the past 4 years. I should have been trying to patch them myself but left it alone since I didn't want to send it in for service with my DIY attempts.

I've been using crocs and have been meaning to switch over to booties. Maybe the tighter fit will keep the socks from moving as much and prevent worn out spots.