Well, there is one item which might be helped by replacement before it ' goes south'.
Some Reciever Dryers have a bag which holds the dessicant. When this gives way due to age or vibration it lets this stuff go downstream. This is always a bad deal. If you want to evacuate,replace the R/D , ( adding back the same amount taken out by the old R/D from a newly opened can of oil ) and put in an inline filter to make sure that if the new one gives way in a few years the stuff will be caught before it gets to the Compressor I would not consider this a terrible thing to do. .... ( unlike Larry) lol.
If you can find a R/D which holds the dessicant in a Wire container you will be upgrading the system when you do this job.
Keeping the fins clean on the condensor is important to how long the compressor stays on at any one time... so that should be done often.. and be sure you aux fan is working well... the same applies to its effects on the time the compressor has to be on to keep the inside of the car the same temperature....