Ken typically buys air filters for his central heating and AC on the internet.
The reason Ken does this is because you can buy them in bulk and get one heck of a discount on them this way.
Most of the time when Ken orders the air filters for his central heating and AC they arrive on time when the website tells him they will be arriving. The last time Ken bought air filters for his central heating and AC they were late arriving. As a result, Ken was also late in decreasing the air filter of his central heating and AC. He was completely out of air filters because he ordered later than usual, and just his fortune the air filters that he ordered for his central heating and AC were also late in arrival. They were almost 10 days. So that was 10 days that Ken had a used up air filter in his central heating and AC. Fortunately, it did not do any damage to the central HVAC system or the indoor air pollen levels of his beach house. If Ken had let that air filter sit unchanged for another 5 days or so, there may have been the beginning of some drastic issues with the air quality, followed by his central heating and AC starting to overwork itself. That could have led to a drastic heating and cooling system breakdown and cost Ken money in heat and repairs. He did not want that.