Originally Posted by Hiro11

100% agree. I don't mess around with anything unless it's truly broken.
I carefully wipe down all my bikes after every ride and fully clean them when they need it. Things I do check:
1. Bolts. Make sure everything is torqued to spec. Don't forget water bottle bolts. I do this every few months. It's not common for me, but I've found stuff can rattle loose on gravel. Especially check the stem bolts.
2. Sealant. I fill it up when I can't hear it sloshing around any more.
3. Brake pads. I pull them out every couple of months just to make sure I have material. I live in a very flat area so my brake pads last forever and I need to ensure I check them.
4. Chain stretch. I have a Pedro's chain checker and keep a stock of all the chains I might need. My chains are inexpensive (I use mostly Ultegra/XT on my bikes), I replace them all the time. (Note: this is yet another reason why I don't wax chains or have some complicated maintenance process...)
5. Freehub mechanism. I have DT Swiss 240s hubs on one of my gravel bikes. About once a year, I'll pull it apart and clean and relube the star ratchet with some special, thin grease that's expressly for this purpose. I don't mess with my other hubs, but the DT Swiss is so easy to overhaul that I take care of it.
6. Tires. I check to see if there's embedded gravel in the rubber after every ride. I dig whatever's in there out with a utility knife. I find stuff all the time.
7. Spoke tension. I check to make sure nothing is coming loose when cleaning the wheels. I've found this to be a problem on cheap OEM wheels. Expensive or aftermarket wheels rarely detension.
8. Pedals: I have Shimano SPDs on all of my gravel bikes. It's super easy to pull them apart and relube the spindles, something I do when the pedal rotates without resistance. It takes at least two years for that to happen, though, so this is a rare service.
9. If you have Shimano mechanical, I would consider replacing your rear derailleur cable once a year regardless of if it's giving you trouble. They tend to shred within the lever body, which can cause them to break during a ride. Also, it's annoying to dig the cable end out of the lever. I no longer have a gravel bike with Shimano mechanical, but I used to and this was a problem.