A small server-side utility mod to create an objective and automtically track play time in minutes, hours and days. There's also data stored in /world/stats - the mod automatically loads this data when a player first joins, so you don't have to worry about manually setting everyone's data, it's all done for you!

OP Commands
/playtime toggle_display_rotation - Enables/Disables the rotating sidebar timeplayed display.
/playtime set_display_rotation_interval <interval> - Sets the display rotation interval in seconds.
[PlayTime]
#World directory name to load old tickTime stats.
worldName = "world"
#Interval in minutes to update play time in minutes.
#Range: > 0
sqlUpdateInterval = 5
#Whether the sidebar display should periodically rotate time played displays.
displayRotationEnabled = true
#Interval for the display to rotate to a new objective every x seconds.
#Range: > 1
displayRotationSecondsInterval = 3