In your schedule, how do you divide the hours?
Your appointments start at the fixed time (10h, 11h, 12h, ...) and last one hour or a multiple of an hour.
Your appointments always start at the fixed time or at the hour and a half (10:00, 10:30, 12:00, ...) and last half an hour or a multiple of half an hour (30min, 60min, 90min , ...).
Your appointments start at the fixed time, the hour 20 or the hour 40 (10:00, 10:20, 12:40, 13:00 ...) and last 20min or a multiple of 20min (40min, 60min, 80min, ... )
Your appointments start at the fixed time, the hour 15, the hour 30 or the hour 45 (10:00, 10:15, 10:30, 10:45, 11:00, ...) and last 15min or a multiple of 15min (30min , 45min, 60min, ...)
Your appointments begin at a fixed time, or 10, 20, 30, 40 or 50 (10: 00, 10: 10, 10: 20, 10: 30, 10:40, 10:50, 11:00. , ...) and last 10min or a multiple of 10min (20min, 30min, 40min, 50min, 60min, 70mn, ...)
Your appointments start at the fixed time, time 5, time 10, time 15, ... (10:00, 10:05, 10:10, 10:15, 10:20, 10:25, 10:30, ...) and last 5 min or a multiple of 5 min (10 min, 15 min, 20 min, 25 min, 30 min, 35 min, ...)