In the Settings> My profile page, in the Preferences section, you can add or edit time entries quick-add buttons that you can use when adding time entries.
Indeed, instead of manually entering time values, you just click on these buttons. Example: your time entry has a duration of 1hour and 30 minutes, you can click on the button 01:00 and then on the button 00:30 (or 3 times on 00:30)