Bookings that start on the dot and last a whole number of slots — per resource when needed.
10:07 to 10:52, really? Without a grid, every booking picks its own time and the schedule ends up full of ten-minute holes nobody can use. The fixed slot grid puts everyone on the same beat, and it can be tuned finely: one duration for the account, another for a tag, yet another for a specific resource.
In the main settings, the slot duration (15, 20, 30 or 60 minutes) sets the minimum length of a booking. Every booking lasts a multiple of that value.
Tick "Enforce fixed slots". From then on a booking must also start on a slot: 10:00 or 10:30 with a 30-minute grid, never 10:07. Before enabling, SpotBooker checks upcoming bookings and lists those that don't fit the grid. They stay unchanged: the grid only applies to new bookings and edits.
A tag can carry its own slot duration, say 60 minutes for classrooms and 15 minutes for lockers. Resources whose duration mode points to that tag adopt it.
On a resource, choose where the duration comes from: the account value, a tag's value, or a value of its own. It is the same inheritance mechanism as check-in and validation.