You see the term CLA thrown around quite a bit in the analogue photography worlds, in reference to equipment. It means, literally, Clean, Lube, Adjust – meaning a service by someone qualified to do such things. Just making sure everything is in working order.
With my mum’s camea, it was a $350 job and the camera and lens was taken apart and re-lubed and cleaned out of 20 years of dust and dirt that’d built up in her travels around the hemisphere. Even the cloth shutter housing was dismantled.
A more standard, cheap CLA, might cost you $25 and involve little more than a once over with a microfiber cloth to clean up the external dust. It can be safer to specify to your repair person exactly what you want done – dismantle and clean the prism housing, this bit here feels stiff to move, re-lube that – and so on.
As always though, you get what you pay for. If you’re not paying much, dont expect much, most repair people work on an hourly rate.