Success in grad school doesn’t come from working incredibly hard.
It comes from setting unrealistically fast deadlines for yourself. And then meeting them.
Sometimes that means working early mornings, late nights, and weekends. Sometimes it means coming up with a new approach, getting the results in three hours, and sneaking out of lab at 3:30. But the point is the results are what matter. If you can find ways to be unexpectedly productive you’re much less likely to burn out entirely than if you can only ever meet your own deadlines by burning the midnight oil at both ends (mixed metaphor intended).
Working hard for the sake of appearing to work hard (either to others or to yourself) is the surest road to burnout and lack of results.
P.S. Productivity goes up at least 5-fold when not also teaching.
P.P.S. If the reagents you are working with are as old as you are, you need to worry. (That falls into the working hard but not getting results category.)