B9exchange At least you know they are safe. Years ago I adopted a tiny rescue kitten who was absolutely terrified of everything and didn't want to go out at all, even if I was with her. She would sit on the threshold and watch me, but was too afraid to venture out into the garden. This was such a relaxing time for me as I always knew where she was and when I mentioned it to the vet, he said "Well, you always know she'll be safe."
When she died and I had 2 more rescue cats, they were keen to go outside as soon as they'd been neutered and had their jabs, and my life became incredibly stressful.
Friends would phone me and tell me they'd seen the boy cat way up the road, twice he nearly got run over but I managed to wave down a car as he began to run across.. He was only 18 months old when his luck ran out.
His sister pined dreadfully for him so I got another kitten as a companion, and this time got a female thinking she would wander less .... but no, she turned out to be a wandering female, and 18 months later she, too, was hit by a car.
I just couldn't stand this heartbreak any more, and so now I have got the cat netting mentioned above, and life is so much easier.