In order to reduce clutter and unnecessary duplications on your public booking page, Bookem allows you to add different durations for the "same" service - see example below, Follow up Consultation - with duration options of 30 minutes, 45 minutes of 1 hour.
To do this, when adding or editing a service, in Settings - Services , simply select the "+" and add the next duration, that way your client can select the time from the drop down that will appear on the public booking page.