Upgrading a Savage ?

Have a Savage 10T 308. Awesome rifle. Bolt has a little slop but not much. When folks talk about having the action or bolt trued (not sure the lingo), when is it a good time to have this done? When replacing the barrel? Its a 5R rifling barrel. Or can the work be done on a stock rifle? Like I said, its a nice rifle but wouldn't mind making it better. The new stealths are supposed to be trued but not sure exactly what work is actually done. Appreciate any info.

Mine is too but my WZ 78 has a better bolt, then my 308, it's a bit sloppy