The valve under the sink that will not turn
If you have lived in your house a few years, you have probably already had the moment. A supply line starts weeping behind the washing machine, or the toilet runs and won't stop, and you reach for the little oval handle under the fixture expecting it to shut things off. Half the time around Republic, it doesn't move. It's seized, or it turns and nothing happens, or it turns and the drip gets worse instead of better. That's usually the first sign something has been ignored for a long time, not a sign that anything dramatic is wrong yet.
Shutoff valves aren't built to last forever untouched. They're built to be used. A valve that sits in one position for ten or fifteen years, which is common in homes built during Republic's growth through the 1990s and 2000s, tends to corrode or mineral up right where the stem meets the body. When you finally need it in an emergency is the worst time to find out it's frozen.
What the local water and weather do to valves
Southwest Missouri water carries a fair amount of hardness, and over years that builds up inside valve bodies the same way it builds up on a shower head. That mineral scale is what locks a gate valve in place. Homes on the older side of town, especially anything built before the 1980s, are more likely to still have those multi-turn gate valves rather than the quarter-turn ball valves that resist scale better.
Temperature swings matter too. Our winters aren't brutal compared to places further north, but we get enough hard freezes, plus the occasional ice storm, that exposed plumbing in crawl spaces and unheated garages takes real stress. A valve that's already stiff from mineral buildup is more likely to crack or snap off at the stem exactly when a pipe bursts from freezing, which is the moment you need it to work without hesitation.
More on this from Testing Every Shutoff In The House Once A Year.
What to actually check once a year
Pick a weekend, maybe when you're already doing fall yard cleanup before the first freeze. Go to every shutoff in the house: under each sink, behind the toilet, at the washing machine, at the water heater, and the main shutoff where the line enters the house. Turn each one a quarter turn and back, not all the way off, just enough to feel whether it moves freely or fights you.
If a valve turns smoothly and you can feel water stop when you close it the rest of the way, you're in good shape. If it's stiff, squeaks, or won't move without you leaning on it, that's the one to flag. Don't force it. A frozen valve that you crank hard on can shear off at the stem, and now you've got a worse problem than you started with, sometimes a geyser you can't stop without shutting off water to the whole house or street.
The main shutoff deserves its own look
Most houses in Republic get water from city service, and the main shutoff is usually in the crawl space, basement, or a utility area near where the line enters, sometimes near the water meter at the street. This is the valve that matters most and gets touched least. Test it the same way, a partial turn to confirm it moves, and know where it is before you need it at 2am with water coming through a ceiling.
If your house has a well, which is still common on larger lots outside the city limits, the shutoff setup is different and often includes a pressure tank valve as well. Worth tracing the whole path once so you're not guessing during an emergency.
When to stop and call someone
If a valve is frozen, if it drips after you close it, or if you hear water running somewhere when everything upstream should be shut, that's past the point of a homeowner fix. Replacing a shutoff valve means cutting into a supply line, and if the main line is old galvanized pipe, which turns up in a lot of Republic's older housing stock, that pipe can be more fragile than it looks once you start working on it. A plumber doing a general inspection can replace a handful of bad valves in an afternoon, usually for a cost closer to a routine repair bill than a major one.
The annual check itself costs you nothing but an hour. What it buys you is knowing, before anything goes wrong, which valves you can trust and which ones need attention before winter or before you leave town for a week. That's the whole point of doing it every year instead of finding out during the flood.