Never? They'll just keep using shittier and shittier gear. Or they'll just hire people we trained, who have our gear, to fight for them in Ukraine. Looking at you, Afghanistan...Serious question: at what point will nations start running out of ammo to "sell" to Russia? NK's only going so deep into its reserves. China...don't see it. Belarus certainly can't possess massive stocks of viable ammo to give away AND reserve some for national defense. If Russia's industry could keep up, none of this would happen. Russia is expending more ammo than it can beg, borrow, buy, steal, or manufacture, and is still losing the war.
It's like I taught my daughter when she was watching me play Medieval Total War years ago: "if you can't have good troops, have lots of troops." Russia has LOTS of troops. And absolutely does not care what happens to them.