You want to switch this over to another forum like General discussion or A/C or Refrig & Ice. You will get more help that way.
My two cents worth though, is this:
Compressors love to be cooled. Either cooled by air or coooled by freon coming back at the right temperature.
They love having the correct voltage and frequency fed to them in a very reliable form. They dont like variations or intermittant actions in this area.
Compressors love lubrication like a hog loves slop! They almost cannot get enought of it.
And they like it clean, and fresh and not dirty or muckey. And they dont like their oil to be very contaminated either. They do not like acid or mositure, (which combined with HEAT, helps to creat acids), and they do not like air or other gases in the sealed system which constitute "non-condensible" gases. These gases do not compress and change state from a gas into a liquid which the compressors love to do.
Non-condensible gases wreak havoc inside the sealed system.
They introduce moisture, other contaminants, and they leave the system running at elevated pressures.
Last but not least, compressors love CLEAN!!!
They dont do well with dirt of any kind in any form.
Compressor love vapor. They only pump VAPOR!!! Compressors do NOT pump liquid!!!
Compressors dont like it when their discharge temperatures exceed a certain peak. For some units it 160F degrees and for others it is a little higher like 240. But 240F is really too high for anyone. But each has their own range.
What kills or harms or causes units to lower their capacity is the folowing.