Remember that Heating and Cooling systems work the best when they have clean filters. Replacing them is simple. Just buy the new filter, walk over to the AC unit and pull out the old filter and put the new one in. A good rule of thumb is every 45 days.
I recommend setting a repeating alarm on phone or computer to remind you. A clean filter means your system doesn’t have to work as hard and will provide you with service for longer.
Grab a couple of extra spares and replace them every couple of months for the best results and efficiency. Here are some useful tips: https://www.energy.gov/articles/energy-saver-101-infographic-home-cooling