The answer varies greatly based on how your system was designed. A properly designed system can go up to 90 days before needing changed. A poorly designed system may require filter changes before 30 days. As a general rule my recommendation is to check your filter every 30 days and change as needed.

This could be a sign of compressor troubles in your outdoor unit. A qualified technician is needed to determine the exact cause.

Absolutely! You wouldn’t drive your car for years without changing the oil or washing it. You should treat you’re A/C as an investment; it very well may be the most expensive appliance in your home.

The short answer is yes. Everything from internal components, cosmetics, and part warranties can vary between brands. The important things to compare are the sytem BTU (BTUs = A/C power), compressor BTU, SEER (energy efficiency) and the warranty.

A ton of air conditioning is the equivalent to 12,000 BTU (British Thermal Units). A 3 TON unit for example should have a capacity of 36,000 BTU. Some manufacturers though will short the capacity of the compressor to increase the energy efficiency rating (SEER). Always compare compressor ratings for accurate system sizing.