ActiveSync will schedule it's self to f*** at least once every 2 weeks. but I only need it for new apps that "have to" use it and mobipocket which I am replacing with mdigger soon enough. Plus I send dbk backups every sunday night to the desktop via BT Sync.
I can only imagine how long it takes, luckily I'm sleeping when it does...
Other than that I let emoze sync all my PIM info with outlook.