Even though Moen estimates that valve cartridge replacement should be an easy, 10-minute job, they must be thinking in terms of pristine faucets with no corrosion or hard water deposits, but that's not Real Life. I struggled over an hour yesterday on a handyman job extracting a Moen valve cartridge from a kitchen sink, having to grab the brass stem with Vise Grip pliers and stand on the counter to be able to get enough pull on it. I managed to raise the cartridge enough to pick the upper o-ring off, but it seemed to be wedged at the lower o-ring or valve port seals. Sure enough, when the cartridge finally came out, the lower valve port seals had been ripped loose. Within five hours I got a call that the new cartridge was leaking worse than the old one, so today I'm going back to swap out the entire faucet, as the client had fortunately already bought one in anticipation. (Unfortunately, their replacement of choice is another Moen!) About 20 years ago I had an identical experience with my own Moen bathroom sink faucet where I wasted $25 and a couple of hours of my time, only to have it leak worse than before.
Bottom line: If you need to replace the valve cartridge on a Moen faucet, regardless of its age, rip the damn thing out and replace it with a Delta or Peerless, preferably one that uses the original stainless steel ball valve element. The engineering is much better, they have fewer parts, and they can be maintained.