200 miles per weak on the city streets.
buy an extra chain, swap them on saturday, dunk/soak *them clean in solvent ,
and be ready to do it again next saturday..
*or wax pot.
Probably go through a cassette and a pair of chains at least every 6 months , I'd guess..
Given that's 5200 miles ..
YMMV...
Maybe one of those plastic tank chain-cleaners, every few days..
wipe off the outside, oil there does not matter, under the rollers is what wears..
.....