You'd figure it out eventually, especially if it was exceedingly annoying and/or your job depended on it.

Example: what if your internet drops out for an hour every Sunday morning at 2am? You'd notice. (Mine does. Damn it Comcast!) If guy's wife relied on the printer similarly, it might be as acute as losing internet for you.

You wouldn't notice if you printed things on average once a week. But if you printed multiple times a day you'd soon notice the pattern, I suspect.