I once had a boss who stalked the halls every evening to see who was still working, but in the early days of Microsoft, Bill Gates had a sneakier way of determining who stayed late and who had already checked out. "I knew everyone's license plates," Gates said, "so I could look out in the parking lot and see when did people come in, when they were leaving."
That's hardly surprising for Gates, a guy who worked weekends -- as the Dowager Countess would say, "What is a weekend?" -- and who "didn't really believe in vacations."
Gates said he "had to be a little careful not to try and apply my standards to how hard [others] worked," but still: He knew.
Which raises an interesting point: Do hours worked matter, or do results?
I've known plenty of people who put in long hours but accomplished relatively little. Sure, they were in early, but they used that time to settle in. And they stayed late, but they spent that time schmoozing and BS-ing and complaining about how many hours they had to work.
They were at work, but not working.
Results matter more. Hours worked are irrelevant -- tangible, valuable results are everything.
That's why you must hire people you trust and then trust that they will perform. (Besides, constantly worrying about what your employees are doing is a waste of mental energy.) Trust is key: If you can't trust your employees to perform, they shouldn't be on your payroll.
Eventually Gates realized that managing by results was more important -- and a much better use, as a leader, of his time.
And that's the flip side of trust: When you show your employees that you trust them, they start to trust you.
Don't worry about how many hours your employees work. Lead and manage by expectations and deliverables.
Not by "butts in seats."