Now at 6 month mark in war.
The RuZZian volunteers typically sign a 3-6 month contracts.
I have to believe a huge percentage of those volunteers won’t want to renew their contracts as they expire.
If they are conscripts, they do not have to serve outside of Russia. If they are professionals with a contract, they can refuse to serve in Ukraine.
There are many outs which is why Russian announced troop numbers cannot be relied on to reflect an actual number - which numbers are so bad, that even the commanders do not know the real number of troops under their command.