I used to obsess over my chain and wasted a lot of time on cleaning my chain and cogs. Then I found more important things to do with my life and just wipe and lube after particularly heavy rains every month or two. Same chain and cassette 3 years later still working fine, despite the caked on crud. Probably get another 6 months to a year out of it and then replace. Saved me countless hours of greasy chain fiddling. YMMV