It worked out fine and didn't cost much at all, only took a half hour (with experience, I could now do this in 10 minutes or less). It was so easy even a caveman could do it!
The shower valve stem had gone bad. At first, when it started acting up a few weeks ago, I thought it might be my imagination or something wrong with the water heater. The hot setting I use started to become hotter, getting progressively worse, and then it became so hot that it was nearly scorching. When trying to get it just a tad cooler this morning it suddenly became cold; there was no in between.
So I asked the guy at Lowe's what might be causing that, since it didn't seem like it was the hot water heater at this point but the valve instead. It was the valve stem he said and told me what I needed plus how to install it. $13 and change and a half hour later the thing is like brand new!
My peeve is this: I've installed two garbage disposals over the past quarter century. That's one that, if you don't do it regularly, requires learning how all over again and it Ain't Easy! And even a simple faucet replacement wasn't quite so simple as I had hoped/expected. I've replaced many a toilet tank flapper and flush mechanism and even a couple whole toilets and tanks. Throughout all these projects I gained a lot of respect for plumbers and what they charge. However, the same plumber would have surely charged me a minimum fee of some exorbitant amount for this little easy repair and many would likely have told me it was much more involved, sold me a new water heater if I was naive, and then not have some "special" parts that he'd have to come back with and charge even more.
Now I know plumbers have to eat too (hopefully they wash their hands very very well each time before they do, LOL) but the rates they charge are amazingly high and so often they don't even get it right the first time. I'm just thankful for the guy at the store who showed me right to what I needed and explained how to get it done. I'm no huge fan of Moen either (I think it should have lasted more than 15 years, it's only used once or twice a day) but at least it was a readily available part and reasonably priced and didn't require any special training or tools.
Even the fixtures seem to be terribly over priced. What's up with that? I saw simple faucets and bath/shower fixtures that were in the hundreds of dollars. Precious few of them had any special features. Brass is nice but not for that kind of money. The style on some was more attractive yet not worth hundreds more than the basic decent looking ones. I just don't get how some folks will spend so much for plumbers and fixtures or toilets or sinks. If it works - great! It needs to be functional and not too hard to keep clean and if I can do it myself just as well in a half hour to three hours I'm going to save hundreds more over hiring a plumber. Are people just afraid of water? And do they really think of their bathrooms as a fashion statement that makes it worth pouring that kind of money into them merely for a little more style?