Please allow a way to randomize the time that a heartbeat/scheduled maintenance will occur.
I'd hate to have 500 clients (yes, I'm an optimist) call home at exactly the same time every day/week, the server would get overloaded. Other applications have had this problem. People always put their cron jobs to update Clam AV definitions at an even hour, 0100, 0200, etc, and as a result, the servers were incredibly busy at those times and pretty dead on the rest of the time.
If you could tick a box that was "random time between x and y" that'd be better.