The best service you can do with A/C is use it, at least half hour every 3 weeks. when its running the oil in the compressor is run around the system, lubricating all the rubber seals on joints, when the A/C is turned off, most the oil returns to the compressor, bottom of condensor and evaperator, so if the A/C isnt used for a while the seals go dry and leak refridgerant.
But a lot of leaks ive found working on car A/C is the condenser ie stones puncturng the rad.
If it smells when you switch on your A/C, remove your pollen filter, get some A/C freshner from a motor factors, spray it where the filter should be whilst the blower is on full so the spray covers the evaperator. job done
The last thing you want in an A/C system is moisture and crap from another cars A/C because it blocks the system when it freezes, every time you connect gauges there is a risk, so if it aint broke dont fix it
