The filter looked worse than I expected
I used to think of well water as just part of the house. Sometimes it smelled earthy after heavy rain. Sometimes there were orange-brown marks around the drain. Sometimes the shower head got crusty around the nozzles.
Then I saw the filter. It was dark, gritty, and coated in residue. That did not make me panic, but it did make me rethink the water I was standing under every morning.
Once you have seen what a filter catches, it is hard to ignore the water rinsing over your skin, scalp, and hair every day.
Well water is not the same in every home, and a shower product is not a replacement for testing or a full water system when one is needed. But it made the shower feel like the most logical place to start.