It's fairly easy (drill hole, inject ink with syringe, seal hole with soldering iron) but it's pretty messy. It's good to have a work area you can fuck up and latex gloves are a good idea. I don't know how to reset the chips, but I keep a set of new full cartridges separate from the ones I refill and when the dialog shows up saying the printer is out of ink (even when the refilled cartridges are nearly full) I just pop in the new carts and print one page of something, then put the refilled carts back in and they'll work for a few weeks until I have to do it again.

Well worth it financially - a set of new carts is $70 whereas $30 of raw ink + syringes will refill the carts like 10 times or so.

I can't speak for all of them, but mine is pretty easy. Their ink cartridges are expensive too, but there's really good third-party options on Amazon