This might come as an unexpected to you, but one of the very most common sources of illness and allergy symptoms in homes and offices will be the carpet. It's not that the carpet itself is the main cause of these issues, but carpets can retain lots of different types of thing within their fibers. They can retain allergen-inducing particles like pet hairs and pollen, plus they can also retain bacteria and fungi that can cause illness. They may also retain odors from spilled beverages and other sources that can stay in a home or office for a very long time if not cleaned out properly.
Uncleaned carpets will also be a huge cause of insect infestations by both ants and cockroaches, because it's quite easy for particles of foods and beverages being lodged in the carpet. These infestations are unsightly and unpleasant as well as hazardous to health due to the allergens and bacteria why these insects can spread. So it is very important to make sure that you get a carpet cleaned regularly - I was having allergic reaction issues during my office, and I eventually experienced my boss to hire carpet cleaning service services. I was much better afterward.