I know a lot of people like a carpet cleaner but I don't. I have been told by professional cleaners (and friends) that if you don't get all of the soap out, the carpet will attract dirt. This happened when we moved in to our house and the previous owners had used a carpet cleaner. We ended up replacing the carpet because it was going to be less than paying a professional every year. Now, no big cleaning and no spots after 2 years. We use Folex as a spot cleaner only.
Oh and we have carpet under our main eating table and no spots so far with spot cleaning only.