At the first time, you may be happy by managing a dozen of sites but after 1 month exactly you will feel extremely tired and need a moderation team to continue work because it is tiring to handle them and you may sell some of them and keep finally as you say 2 or 3 websites.Wow, so you seriously work on about twenty sites online? That's just incredible. I am handling just three to four sites and it's like the limit I can take, you must really have a lot of spare time