Most ball valves nowadays are teflon seated hence need no lubrication.
If you accumulate a lot of bio-growth or roughness on the ball you will tear/abrade the PTFE seat ... so you 'ought' to get in there and inspect/clean once in a while. The balls themselves once they become rough - its time for a new valve. The PTFE seats are replaceable but still need a perfectly spherical ball to operate well - dont even think about 'sanding' or coarse polishing a ball.
At least with the old fashioned tapered plug
valves you can 'lap' them (by hand) back into good working order with automotive valve grinding compound. Pay me now or pay me later.