Shouldn't be too many reasons not to after the original warranty is up.
You seem to be alluding to voiding of the warranty. Please keep in mind that there are other factors in play.
For instance: 1) Ruined prints when one of the cartriges runs out with no warning and the machine continues to run on...printing. That's time and materials lost.
2) That line through which no ink was being pulled, will now require some siphoning to get it started flowing again. And hopefully you've not had the head dry up in the meantime. That's time lost.
I
twice had this happen and informed my wholesaler both times. They basically told me tough luck, that it shouldn't be happening, but
it can happen. And....here's the kicker. If I remember correctly, the savings was only about $5.00 per cartrige over the original ink cost.
Not worth it in my opinion.