Most of the air-conditioning unit will run for years with no maintenance at all, but just like a regularly serviced car can avoid costly bills when a breakdown does occur.
AC unit is a very rugged piece of equipment. They are produced with high quality and designed to withstand all types of environmental conditions. They are often overlooked for maintenance purposes but regular maintenance can save money on the expensive failure of the entire system. You can get services and installation for all your HVAC needs from professionals.
When the air conditioning unit or heat pump is not maintained, then it will lose the efficiency of about 5% for each year of continuous operation. It has a severe effect on the load unit can handle and will make the unit perform poorly.
With proper care, efficiency can go back and routine maintenance will maintain the manufacturer's claim. Maintenance costs will be easily found by savings in electricity bills and properly maintained units will cool, heat and dehumidify more efficient.
As an end-user you are supposed to remove and clean the filter was washed in the evaporator unit (indoor) regularly. Most units have easy to open with a panel directly into the filter element. The easiest way to clean them is to hold them underwater from the tap.
Dry the filter before replacing. Try to clean the filter at least once a month or more often if the unit is operated for a long time or dusty or dirty indoor environment.