i might have seen screen saver activate once on my device, but it takes a very long time to activate.
i dont remember for sure but its something around an hour?
there is no manual activation, but there is low brightness setting, if you care about longevity.
even then i dont know how much it would reduce burn in because its still bright enough to be usable in daylight on low.
if your screensaver doesnt activate, perhaps its receiving clock from midi/usb in.
that said, i personally dont worry about it because i almost never see digis with burn in
plus my unit was a floor model that was probably on for a year or two, and is still in perfect condition.