I have been using Loc8tor Lites for several years now. I used to use them on all three of my cats but two of them barely left the garden and my youngest, Joey, used to travel far and wide - however, he had the habit of losing his collar! I have probably got through 14 collars now for him alone! I only use the 'breakaway' type collar so that he doesn't get hanged on a branch or something. But, of course, this means that the tag gets lost with the collar. I started using the other two cats' tags as I realised that (touch wood!), I didn't really have so much use for them, but am still tempted to put them back on (you never know, do you?)
Anyway, I HAVE actually rescued 3 of the collars by using the Loc8tor tracker as they were within the range of the tracker unit! I wouldn't have a clue otherwise where to start looking. Although people say that I am a bit 'paranoid' about my cats, especially Joey, the joy and contentment that I get from their company is immeasurable. I DO get upset if I haven't seen Joey for a few hours, but as long as I can get the 'beep' on my unit (and preferably changing position regularly, otherwise I would think it's just another lost collar), then the peace of mind is worth the money. But it does get expensive when he keeps losing them, the little tinker!