I used to have that fear. I couldn't go to bed at night unless I counted tails. I finally overcame it when I had 9 (my own plus fosters) this past summer. It was too much to count 9 tails and I felt rather silly hunting down 9 cats! I'm glad I overcame it because I realized it was starting to become and obsessive compulsoive act with me. I could have seen Abby five minutes earlier, but since I didn't see her right before I rolled into bed, I would irrationally fear that in the past 5 minutes she somehow snuck out.

Try this - get a plastic cup with a screw-on lid and fill it with hard treats. Shake the cup and when the girls come running they'll get a treat. After a few times, they understand REAL quick that this means food. So when you leave the house, leave the treat cup by the door, shake it as you're about to leave then offer a treat to both of them right before you slip out the door. They'll come to you much faster than if you simoply offered them a toy.