This is really a fantastic resource that works with existing tools (ie: Google Calendar). I have ADHD and work in an environment with very little structure (good & bad) that requires a lot of coordinating with students and colleagues. This is GREAT and helps to quickly see if there are problems with my settings or (more likely for me) explain why those slots are not available - which is either because the time slot is 'too soon' after a previous appointment or because of 'calendar' which is due to another booking or calendar event. Koalendar has recently instated a 'Troubleshoot' toggle button which can be seen when the owner of the Booking page is viewing their page.
This has genuinely freed up a lot of my headspace. This has completely freed me from the back & forth previously required for scheduling and now all I have to do is look on my calendar to see what I'm doing that day. Now - if anyone needs anything - they can just schedule it themselves and it shows up on my Google calendar immediately (& the other party can cancel or reschedule as needed!). Was very excited to try this tool and after several months I am still excited about it! Previously, my colleagues were asking for meetings & appointments either verbally or via email and I was drowning in both.