I would like this too, although it seems like a workaround for Sync running and draining the battery (I have activated the Auto-sleep and battery saver, which seem to help). Although I use Llama and also tried to find a way to control Sync to start on certain conditions (works) and close on other (doesn't work), an even better way would be if Sync had a built-in mechanism to wake up, sync, and then shut down on certain conditions ("Connected to any Wifi", "Connected to specific Wifis", "Day of week", "Time interval", "Charging" seem to cover most requests). I am fully aware that a selling point is "immediate sync", but considering the many scenarios Sync can be used, "immediate" is not always required. Nevertheless, Llama and Tasker support would be a great feature! Thanks!