I've bought the Business Calendar app for Android, and it's a great program. But one thing I've always wondered with calendar syncing in general, is which way the sync works, and if it syncs both ways and the two calendars have differences, then how does it know which side the changes should be applied to? I only use the Business Calendar (on which I use my Google calendar) on my Android, and not on my computer, and I regularly back it up to my PC by exporting the calendar to a csv file. But on discovering that sometimes I was unable to delete an individual occurrence of a recurring event in Business Calendar on my phone, and then reading on the website that you have to sync the calendar with Google for it to work, it seems I will have to sync my Android calendar with Google calendar on my PC. Although sometimes I can delete an individual event, so it's a bit strange. Maybe I created those events on the phone rather than them being part of an imported calendar. So how does sync work?