Don't you wish you could see what your feline companions do when you're not home. When we pull in the driveway, there he is sitting in the window faithfully keeping his vigil. Does he sleep most of the time? Does he sit in the window all day? Does he chase imaginary mice around the rooms. Does he have separation anxiety? Cameras all around the house connected to my computer might give me an insight into his behavior, but then every person in the house would lose their sense of privacy.
Maybe some things should remain a mystery. Cats are a mystery anyway. So, if you must leave them home alone, never for a long time, and make sure they have plenty of water and some food to tie them over, and a clean litter box. Common sense eh? But when you're in a panic to go out the door to catch a bus, or to get to that important church meeting, take a deep breath and ask yourself, "Have I forgotten anything, especially those little critters that depend on me so much?"
Cats need us more than we need them. They like to put on airs of independence, but in reality they are so dependent on us. They'll never admit it, and don't tell them.