That drip under the sink you keep ignoring
If you're noticing a slow drip at the base of a faucet handle, or a puddle forming inside the cabinet under the kitchen or bathroom sink, the faucet itself is usually not the whole story. A lot of Nixa homes, especially the ranch-style houses built through the 70s, 80s and 90s around the Christian County side of town, still have their original supply lines and shutoff valves. Those parts are often thirty or forty years old even if the faucet on top looks newer because someone swapped it out once already without touching what feeds it.
When a plumber or a homeowner replaces a faucet, the supply lines and shutoff valves usually come along for the ride, whether or not that was the original plan. That's worth knowing before you start a project, because it changes both the time it takes and what you should expect to pay attention to afterward.
Why Nixa's older valves tend to fail at exactly this moment
The compression valves and multi-turn shutoffs common in older area homes get worked maybe once every few years, if that. Most homeowners never touch them between faucet replacements. When you finally turn that valve to shut off water for a repair, the old washer or seal inside can crack or the valve stem can seize. It's common for a valve that hasn't been touched since the Clinton administration to start weeping water the moment it's turned, even if it looked fine sitting still for years.
This isn't really about bad luck. Rubber and old brass don't like being disturbed after decades of sitting still, and our water here runs somewhat hard, which adds mineral buildup around the valve threads over time. That buildup can make a valve either impossible to close fully or unable to open smoothly, both of which show up right when you're mid-project.
More on this from Supply Lines And Shutoffs That Get Replaced With The Faucet.
What freeze and thaw does to the lines feeding your fixtures
Southwest Missouri winters aren't brutal by northern standards, but Nixa gets enough hard freezes, usually a handful of nights each winter, to stress older supply lines, especially in homes with plumbing routed along exterior walls or through unheated crawl spaces, which are common in this area given how many houses here sit on crawl foundations rather than full basements. Braided steel lines handle that stress fine. The old rigid or plastic lines from decades back don't always.
If your home has a history of frozen pipes, or if the faucet you're replacing sits on an exterior wall in a bathroom addition, it's worth having someone check the condition of the supply lines specifically for stress cracks or brittleness, not just leaks. A line that survived last winter by luck might not survive the next one.
What you can check yourself before calling anyone
You can look under the sink right now without any tools. Check whether the shutoff valves feel corroded or have mineral crust around the handle. Try turning them gently, just a quarter turn, to see if they move freely or feel frozen in place. Look at the supply lines themselves: if they're the old brittle plastic-coated kind rather than the flexible braided stainless kind, that's a sign of age worth noting.
You can also check for slow leaks by laying a dry paper towel under each connection point overnight and looking for dampness in the morning. If everything's dry and the valves turn smoothly, you're probably fine to handle a straightforward faucet swap yourself, or to hire someone for just the faucet.
Where this stops being a weekend project
The line gets crossed when a shutoff valve won't close all the way, when it's corroded to the point of crumbling, or when you can't find a working shutoff at all and the only option is cutting water to the whole house. At that point you're not replacing a faucet anymore, you're replacing plumbing behind the wall or under the floor, and that's a different job with different risks, including cutting into drywall or working in a crawl space that may not have been touched in years.
If the shutoff under your sink hasn't turned in longer than you can remember, or if you see any greenish corrosion on copper fittings, that's worth having someone look at before you start pulling the old faucet off. It's a lot easier to deal with a bad valve on your own schedule than to discover it mid-repair with water already off to the house and a hardware store forty minutes away from closing.