Cat vomiting

Just looking for a bit of advice really. I have 2 kittens (almost a year old) who are both rescues. Recently one has started to vomit, however, I'm not sure which one it is! They never vomit when I'm at home, only when I'm out. And at times it can be in 2 or 3 different places. Generally it's just a bit of slightly digested food.
One of my cats has a slightly watery eye but otherwise appears healthy.She eats well (but often quite fast), hasn't lost weight and is a little monster. However, she likes to shred cardboard so I'm wondering if she's maybe eating it as well and that's making her sick.
The other one also appears healthy. Is eating ok, not losing weight etc. She has previously had chlamydia which was successfully treated, however, she has previously done two poos which have had traces of blood on them.
Also the other month one had worms but they were both given tablets for that.

Basically I'm looking for advice as to what I should be doing and whether I should be worried (I've previously had dogs but not cats). Obviously it's difficult when I'm not exactly sure which cat is vomiting and I don't want to be paying out massive vets bills if I don't have to.

Hello and welcome to TCS! A few questions: do your kittens have all their vaccines? Did you do just one treatment for worms? Is there any residual goop or crust on your kitty's eye?

I've attached an article that might be useful to you:

http://www.thecatsite.com/a/your-cat-throwing-up

Thanks
Yes they've been fully vaccinated however haven't been neutered yet (but they're indoor). They did only have one worms treatment but I think I have more tablets and I can always get more. Plus I've never seen worms in the vomit. As for the eye it's not crusty or goopy, just waters a bit more.

Also at the moment they only eat dry food as one had a very smelly bum when on wet food. There's always food out so there's no rush on them to eat and they just pick at it throughout the day.

Just a quick soapbox: I hope you plan to get your kitties neutered, just in case one gets out by accident. You won't be left with kittens, but some poor mamacat on the street will!

If the vet was satisfied with one worming then so am I, although typically kitties are treated twice a couple weeks apart.

I would watch your kitty's eye for any goopy discharge in the future, as this would indicate an eye infection that is treatable with antibiotic ointment.

As for the vomiting: how many times a day for how many days has this been going on?

They're both female so I'd be the one left with kittens! But yes they both will be done. I just want to make sure I do it when I can have a few days off after to keep an eye on them.

The vomiting has been happening for a few weeks. Some days there will be nothing. Other times there will be 2 or 3 bits when I get home. As I say it's never when I'm around. It's either when I'm at work or when I'm asleep.

I would say contact your vet to see what s/he thinks. If a medical cause is ruled out then you can explore nutritional or other causes. Cats are very good at hiding when something is wrong with them, so keep an eye out for any other symptoms that show up