How long for a set of rear brake pads. 3852miles

Reason , dp my mechanical mentor  :bowdown: rekons pistons may have bin seized when i got the bike at the beginning of April with 1248 miles on the clock.
When did I find out? When i erd a crunching type sound and seeing I was visiting dp asked his advice. Picture of a wise OLD owl.
Own fault really as should be part of the weekly checks that includes fluids, rubber, electrics, suspension and brakes.
What does everyone else check and on how regular a basis?
Big thx to DP. CU when I get back with my tan.  :cool: