I rotate 3 chains. Easy to have one ready to install, stored in a zip lock bag all oiled and ready.

I oil whenever it looks dirty on the bike, and always wipe "dry." Usually about every 100 miles or so, and remove for cleaning/reoiling about once a month (every 800-1000 miles).

My chains and sprockets last almost forever, using cheap KMC chains.

Yes, I sometimes overdo maintenance, but I like it.