Keeping the AC compressor clean.
This is a very important point. AC compressors can get very dirty depending on what surrounds the unit.
This unit is surrounded by dirt.
It is also very close to the ground.
The AC compressor should be at least 3" above the soil level to allow for drainage.
Typically the compressor is sitting on a little pad, either plastic or concrete, which can sink into the soil over time.
But it is also wise to surround the unit with gravel or grass or concrete so that rain or water dripping from a deck above will not splatter mud onto the protective cover.
The unit pictured here is covered with mud! It is an older unit which was sitting on its original pad. That pad was at ground level at the time of this inspection. And it was caked with mud.
That restricts air flow through the openings so the coils inside will not be able to dissipate heat properly and this affects the efficiency of the whole system dramatically.
My recommendation: make sure the AC compressor stays clean and air flow to it is not impeded by mud or bushes or fences or anything beside. Air needs to flow freely through the unit so the system can properly function. It is a simple matter to surround the compressor with material that will not splatter back onto the unit. And in this case it should be done right away.