There is always room to improve. That is what I tell my son. He has just started running track. He is only in his first year of middle school. While he is young, he has won every event this year and has not lost a single race. Despite his success, I keep telling him that practice is important and that he cannot just slack off if he wants to continue winning. I don’t really care about having the most athletic son in the world, but I want him to appreciate what hard work can make happen. I always tell him that he can be better if he truly wants to be. He can always be more efficient. He can always be faster. There is no limit to those sorts of things. It sounds funny, but this is the approach I take with my HVAC system as well. First, I believe my indoor air quality is top notch and better than most other households in this area. However, I still attempt to make it better each month. How do I do this? First, I swap out the air filters for new ones almost once a month. Second, I wipe down the air vents. Anytime a little bit of dust forms on that vent, I wash it off so there are not little dust particles being blown around all over the place. Finally, I have my system maintained by a professional twice each year. The combination of all these things keeps my units cleaner than the month before. I will do this stuff until the day that I die.