Four per week seems like it might be a lot for one cat.

Every cat is going to do it now and then - if nothing else, they get fur in their throats and have to cough that up.

But I had a cat that had food allergies and inflammatory bowel disease (that cat has passed away, but now we have another cat that also developed IBD...sigh). That cat did a lot of throwing up. We have three cats now, and I'm cleaning up fewer messes than he generated alone. I miss him a ton, but I don't miss cleaning up the messes.

But, my suggestion is that you note what's in the vomit - are you seeing fur? Undigested food? Digested food? Or just bile? And note the frequency. And then talk to your vet.

for mine its maybe one per few weeks and she has very long fur so that seems like a lot, you should talk to a vet about it