Most important
Clean & lubricate your chain
Check chain wear
Inflate tires
Wheels & Tires
Drivetrain
Charging
Good news! You can record every bike ride to either Strava or RideWithGPS (or both!) for free and then Bike Mec will sync your rides to the app and keep up with all your service schedules.
Without a service keeping track of each of your rides, Bike Mec doesn't know the latest rides, distance, or moving time for each bike. So for Offline bikes service can only be scheduled by the calendar.
Many riders double post their rides to both Strava and RideWithGPS. Why not: it's free, protects you from losing your data, and each site has it's strengths. But if you happen to sync Bike Mec to both services you probably only want to see one of each bike you own. ;)|
(There's a Setting to let you see your bikes again if you hide one by mistake.)