Now heres a suprising bit of advice.
If you want to extend the life of your carpet, its important to have it professionally cleaned at least once a year. (According to most manufacturers)
On average, it will take around 2-4 hours for the carpet to be completely dry.
SUMMER - If its a warm, sunny day, it will dry quicker, also ventilate the room to aid drying.
WINTER - Turn on the heating.
once dry vacuum the carpet for best results.