Just wondering if I should use something as a preventative measure, or only if I see/hear them hacking up hairballs? I do have some treats that are supposed to help prevent hairballs, but was wondering if I should use some of the other stuff too? I can't remember what it's called--something you put on their paws and they lick it off while cleaning themselves.

Hairballs are best prevented. I highly recommend using a hairball remedy to prevent hairballs. You only have to give it once a week. Squeeze a glop of it on your finger and see if your cat will just lick it off your finger. Seriously, it's my cats' favorite treat!! Laxa-Stat is what I'm using now. Laxatone is also popular. Dermcare is my favorite (and my cats' favorite), but I think Petsmart discontinued it. Just be sure you don't give it to them before eating. Two or three hours before is recommended. I've been giving them this ever since they were adopted, and I've never, ever had a hairball coughed up. :)

I don't think much of the hairball food or treats, though. Ineffective.