Not worth running corrosive anymore imo unless you have a huge stash. Non is almost the same
I ran corrosive once through an earlier SKS I owned - thankfully a "beater" one. I didn't know what I was doing in terms of the cleaning regimen so I was using a funnel to try to pour water directly from a kettle into the action/chamber/barrel. Forgot to wear gloves so it wasn't a good scene. Then I realized I could take the receiver out of the stock to run the hot water. It wasn't long that I found it too cumbersome for someone as lazy as I can be so I just started buying non corrosive.
I have since bought some SKSes that have gone through the corrosive route and were never cleaned and with seized piston rods, pitting everywhere, corrosion, etc. - I figured if I can just run known non-corrosive (ie. Barnaul, Norinco white box 311-14, red box 311-19, 311-20 and avoid white box 311-18), the cost difference is a few bucks, but to me it is worth it. I don't mind cleaning the gun as per usual with my cleaning rod and G96, but just taking the metal action out every time is just something I'd rather not do.
I just bought an SKS recently where I am not sure it has had much cleaning at all. Thankfully no corrosion that I could see but the gas tube contents were TAR BLACK, even after running 20 or so patches through it. It took about 22 before the colour started looking better - but the patches were small.
It is true that from a purely monetary and value proposition, corrosive is better value, since in either case, you can't re-use the steel cases anyway and the experience is indistinguishable at the range.
I would think for me, to use corrosive ammo, I'd have to be at the range shooting my SKS for at least 3-4 hours minimum to make it worth it for me to take it apart and run another kettle's worth of boiling water into it and hope I don't scald myself...again...