Rain riding does chew up chains, cassettes, chainrings, etc faster than riding on dry roads. I'll ride any of my bikes in the rain,but they're all 7sp and 8sp so replacement parts are CHEAP.

If you've an old steel hardrock you may want to treat it with framesaver

Repack your hubs twice a year, replace cables once per year, etc

Repack your headset occasionally. Every other year if you have fender, twice per year if no front fender