Do you refill them yourself or buy new ones?

I have a kodak. $22.00 for a black and a color cartridge.

RDP

I buy them as refills and non original cartridges tend to block the heads.

I've got a business grade HP 2230 inkjet, and a massive black cartridge costs £15. Bearing in mind this cart is about four times the size of a consumer one, this is quite cheap. Print heads are replaceable like cartridges which is quite handy.

I have a (really) cheap inkjet, but even if I had an expensive one, I would still buy new ones.
Refill kits are too sloppy to mess with but generic ones aren't too bad.

Peace.

I refill until the head goes bad.
I probably get at least 5 refills out of an HP cartridge, minimum. Maybe more like 10.
($10 refill kit versus $300 of new cartridges)
It's especially nice to refill if you have a three color cartridge and only one color has run out.
One trick I've learned is to maybe half fill it each time.
Refilling gets super messy if you over fill, so by under-filling, you can inject some ink and pop it right back into the printer with zero fuss and no wait.