Shower head maintenance
Here is a more conventional use for WD-40. It is excellent for cleaning your shower head and removing dust and dirt. After a couple of sprays, you will see the difference in water pressure; this way, it lasts you longer and more uses.
Everyone must replace a shower head after some time; it is inevitable, considering how much we use it. But this way, you can extend that time a tiny bit more. With just a little maintenance, you will get to save money on replacements in the long run.