Home again charges an annual fee but Avid does not.

If you go with avid, your vet may charge in the area of $50 for the chip but the chip will be registered to the vet at that time. This means if your pet shows up somewhere and gets scanned, the people will contact the vet who will hopefully give your contact info. You can also register it in your name which your vet will probably recommend and that costs around $20 one time (charged by avid). Vet will give you a form.

The cats were microchipped at the shelters we adopted them from.

I think both companies charge a one-time fee, but HomeAgain has some added services that have an annual fee. Avid offers a one-time fee for up to eight animals. I think I'm going to go with them -- you never know, we might decide two cats aren't enough. :)

Thanks for the input.

Check with your local shelters and see which scanners they have. Home again and Avid don't use the same frequency, so one scanner reads only their chips, and the other reads only theirs but recognizes that there is another chip present. I can't remember which scanner recognizes the other chip. Anyway, it would be really sad to have a chipped cat euthanized because they didn't have the chip that the local shelters' scanner could read.

I called Avid yesterday, and the person on the phone said that I could register HomeAgain's chip with them. I just mailed my check; I'll post back when I hear back from them in case anyone is interested.

I'm certainly not planning on letting either cat outside; this is just in case they get out accidentally. All the shelters around here microchip all pets that they adopt out, so the chips were implanted before we brought the cats home. I wouldn't even have thought of getting them on my own.

I also chose avid because that's what the shelter installs but their scanners will read either one supposedly.
My vet who sells home again chips demonstrated how their scanner will read them all. There's other brands too, like the ones they sell at banfield which I know nothing about other than they wanted like $100 to put it in!

We have Home Again, but only paid the one time fee. I just checked, and that is what it says.

I don't know anything about extras, just what our Vet gave us. We did register them.

Sammy