Is there cooling maintenance for the outdoor unit?

I have never called for cooling service.

I know what to do for my air conditioner. I learned the proper amounts of coolant to put in my machine. I know mold gets on the cooling coil and that it needs to get removed or my air quality will suffer. I change the air filter monthly to avoid dust. I also clean up my condensate drain since the excessive water tends to promote algae growth. I lubricate my fan motor belt, clean the fan blades and tighten any loose screw. I do feel like quite the AC technician afterwards. The only concern is the outdoor unit with my air conditioner. I have no idea what to do for that outside unit. I am thinking the outdoor component must be a little more heavy duty. I mean my outdoor AC plan sits in some pretty harsh elements. I get feet of snow and ice in the winter. Frequently ice falls on top of the unit. There are no dents or rust from the snow melting. In the spring the rain comes down for months at a time. I can’t see any mold, mildew or other bacteria growing inside the device. Yes, it does look a bit dirty. But, I am wondering if it matters if the outside unit is dirty. That air is not being blown into my home. Does the outdoor unit need something done to it? Could my AC be more efficient? I won’t call an air conditioner business. But, I will definitely research to see what I can do with my outdoor unit.

HVAC technology