We recommend having your AC & Heating unit(s) serviced twice a year. Spring maintenance for your AC unit(s) & Fall maintenance for your Heating unit(s). The longer you put off maintenance, the worse your unit(s) can perform and more likely to break down.
Yes it is. R-22 has already been discontinued & has become very expensive. R-22 is no longer allowed to use in new equipment due to EPA regulations. however if your existing equipment uses R-22 there are substitutes available. As R-22 & its substitutes are expensive you may want to consider upgrading your equipment to R-410A, which is the acceptable refrigerant allowed by the EPA.
Everyone is comfortable at different temperatures & no 2 homes are identical In the summer anywhere between 72-80 is recommended. In the winter, anywhere between 68-75 is recommended. If no one is home you could stay within 3 degrees of your set temp desired. Playing catch-up increases your utility bill à puts more stress on your system.
If you notice any ice on your outdoor unit(s), you should shut the thermostat off immediately. There could be man reasons a system will ice-un & an iced-up system cannot be properly diagnosed until it is fully defrosted.
Performing yearly maintenance on your AC/Heating system(s) helps extend the life of your unit(s). AC unit(s) in Las Vegas are extremely challenged with the high summer temperatures, and typically last 10-15 years. Yearly maintenance is the best way to assure your unit(s) works to its best ability & increases its life expectancy.