This is a good question and varies based on multiple factors and individual needs. The only stats we have so far are related to sleep phases which I also responded to another reader. I have copied them here for your reference

Light Sleep (5%)
Deeper Sleep (45%)
Deepest Non-REM Sleep (25%)
REM (25%)

The traditional beliefs are 8 hours sleep, 8 hours work, and 8 hours rest and downtime. This, of course, will not suit everyone’s needs and lifestyle. Thank you for your time to read and comment, Alison. Nice to meet you.