The problem with these groups is that there are many questions and very few answers. To clear my conscience from a previous posted question, here's an unsolicited answer that might be useful to someone down the line:
You can rebuild your Moen (and other manufacturer's) faucet valves by cleaning the existing parts well and then reapplying the RIGHT KIND of o-ring grease. Unfortunately, places like Home Depot will mindlessly sell you "plumber's grease" in little white tubs from companies like Rec-O-Seal which are NOT for use on rubber, but don't say that anywhere on the container. These petroleum-based greases will cause the valve to stick if not used for a couple minutes, although if you work the stem it will temporarily appear to be well-lubricated.
If you buy grease that specifically states "silicone grease" or "for use on rubber o-rings", it'll work like new and you'll extend the life of your value indefinitely. My valves are 20 years old and work as well as a new valve insert, and the o-rings are still like new.
That being said, if you are a contractor and can pass off the cost to the homeowner, the $13 inserts are the way to go. But as a homeowner, I saved about $150 in parts alone by redoing the valves myself.