One consideration that can affect many components in your home is the allergies of the people who live in it. The adjustments that can help depend on the item(s) causing the allergic reaction. Allergies can become more or less severe over time, moreover, anyone can can develop an allergy at any point of one's life.
Allergies to dust, or more specifically dust mites, can be alleviated by reducing the things that can hold dust and additional cleaning. For instance, wood floors are easier to keep dust free than carpeted floors. Curtains can also hold dust. Dust from higher up to lower and then vacuum.
Plant allergies ... easier to handle, if you have control over the yard or no yard. If the allergy is to an indoor plant, consider getting rid of it or moving it outdoors. If it's to an outdoor plant, can you get rid of that plant? Or if it's too common, like grass, could someone else mow the lawn? Some plant, like oak trees, have flowers in the spring. They may not cause an allergic reaction at other times.
Allergies to food... if you need to have the food in the house, keep it away from other foods. Keep it clearly labeled.
Pet allergies... surfaces that make it easier to clean up the hair... good vacuum cleaner.
Perfumes are added to many common household and cosmetic items. Even magazines can have inserts with perfume samples.