It is very important to change your A/C filters regularly. Filters will protect the A/C units and keep your family healthier. Dirty filters also restrict the airflow to your A/C unit, causing it to work harder to cool/heat your home, resulting in higher utility bills. According to the U.S. Environmental Protection Agency, indoor air is two to five times more polluted than outdoor air. This can be a real problem, especially in Texas where everyone seems to suffer from allergies. But on top of that, if your A/C filters are 1" panel filters, (common in older homes) they are not very effective at protecting your A/C unit or your family. In fact, all the 1" panel filter does is stop large particles, allowing smaller particles (most of the particles in the air are small) to pass through and build up in your A/C unit and home. Your home essentially collects particles coming in from the outside air, traps them, and particles build up over time. This makes your air quality inside worse than the air outside, unless you have a 4" pleated-Media filter which filters out almost all of the particles (there are filters that remove 97% of all particles, but are expensive). Pleated-media filters cost about the same as normal 1" panel filters, need to be replaced every 6 to 12 months, (not every month) and can actually make your home's air less polluted than the outside air by cleaning the air inside your home. So, in short, you need to have a 4" pleated-media filter to protect your A/C unit properly, make your home healthier, and can actually save you money in the long run by protecting your mechanical systems and health. Please feel free to email me at matt@goodsellestatehomes.com if you have any more questions about 4" pleated-media filters. We have a coupon below to save $75 dollars on a 4" pleated-media filter set up for your A/C unit.