Most carpet manufacturers recommend cleaning your carpets every 12 to 18 months to maintain your warranty. There are many factors that you should consider that would affect frequency of cleaning; soiling conditions, number and ages of children, smoking versus non-smoking, pets, etc.
Always get someone to look at your carpet in person. There are too many factors involved in cleaning that cannot be answered over the phone and need to be looked at in person.
On average, it will take approximately 20 minutes per room. This time can vary greatly depending on the amount of furniture to be moved, how soiled the carpet is, and any necessary spot removal treatments.
Dry time is affected by humidity, temperature and air flow to the area. It can take anywhere between 8-24 hours for the carpet to completely dry, depending on the variables. Using fans in any rooms cleaned and turning your air conditioning or heating system on, depending on the time of year, can help accelerate drying time. Be sure to leave the protective blocks under furniture legs and any paper used with upholstered items in place until the carpet and/or furniture is completely dry to avoid any color transfer. You may walk on your carpet immediately after cleaning, but avoid wearing street shoes, as they may re-soil your carpet.