Years ago I would set an alarm, but invariably wake up moments before it went off. Then I seemed to lose that ability, and I would be jarred awake by the alarm. For the last few months, I've had a new pattern; I often wake up half or three quarters of an hour before the alarm, and wish I hadn't blown that bit of intended sleeping time.
At least my wife doesn't have to worry about whether to "wake up grumpy, or just let him sleep".