Nailing the apex of your leave
When on leave last week I listened to a Yes Theory podcast that discussed burnout. It's important to find the right length of leave at the right time.
I watch a lot of car racing and optimal performance comes from how a driver approaches, traverses and leaves a corner. Accelerate out of a corner too fast and you'll burnout, squealing the tyres as you go. That risk increases if you break too hard into the corner and miss the apex. But go too slow and you'll struggle to get going again.
Leave is similar. You need enough time to slow down properly so that when you accelerate out the back end and return to work you don't start already out of control.
Wish I could let you know a formula for that other than listening to how you feel and adjusting over time.