Sleep now catch up later?

Not exactly true.

Experts say we need 7-9 hours of sleep everyday to keep us fit and healthy.
The notion of being sleep-deprived frequently and making up for it when we have the time is simply erroneous.

When we don't get adequate sleep, we accumulate a sleep debt that can be difficult to 'pay back' if it becomes too big.

The resulting sleep deprivation has been linked to health problems such as obesity and high blood pressure, negative mood and behavior, decreased productivity, and safety issues in the home, on the job, and on the road.