Yes, there are many things to think of. I think October is the month to have a flu shot. Flu can be extremely irritating to the bronchial tubes and cause a severe exacerbation. Unless, you are allergic to eggs, I feel that a flu shot is needed. If you live in a very cold region, this is a good time to get your cold air mask ready.
Cold air can be very irritating.
Remember also you will be spending more time indoors. Make sure you have allergy proofed your home for the indoor allergens like dust mites, house dust and mold. I like air purifiers for the home but caution asthmatics about humidifiers since they can develop mildew. If you are in a very dry home, however, and clean the humidifier daily, it is acceptable. It is difficult with children in that age group since they often cannot tell use that they are having trouble breathing of the older children can do peak flow readings and there is a device called AirWatch which I like with a cartoon character that the children seem to like.