How do you do it with a busy schedule?

I'm 28 and got my first cat last year from a rescue, he was a year old at the time. Yesterday I saw a post on Chambers where a local cat was in need of a new home due to the owner being homeless and unable to care for it, I couldn't bear the thought of the little furball being sent to a shelter so I took him in as well and I'm just wondering, how do people do it with multiple cats when they have a busy schedule? It can't be a good thing for the cats to be alone for long periods of time, and I'm only two cats deep.<br><br>I've always been an avid cat person, but I don't have the time it appears.<br><br>I have one cat tree, and one scratching post. They're both spayed/neutered and microchipped, and I think I'm about to invest in a litter box for each of them, but I still don't know how to keep two cats happy.