I was wondering how many seasons others re-use cable extensions before they are concerned with them starting to rust on the inside? Are you treating them with paint or dip prior to use?

I use a lot of cable extenstions, I have several hundred of them. I replace them when they get a bad kink or start to unravel. All of mine get a dip in rusty metal primer and acetone as that's what I dip traps in. Just keep an eye on them and inspect the ones you are using. You should get several seasons before needing replacement.

Depends on the type of cable. 7x19 cable extensions last way longer than 7x7's

7x 19 cable?? I’ve ever seen any! Did you mean 1x19 ??

7x19 is where its at for extensions, it has practically no memory. You'll have to order it from a place like snareone or snare shop to find it though. Most general trapping suppliers only carry 7x7, some will have 1x19.

I have been using my cable extensions for many years. I too use them until I deem them too kinked for regular use. Most of mine are 7x7. They do a great job for their intended use in wooded areas or areas with spare trees and rocky ground.