I hope gura has a great stream!
>>1302585>>1302731>>1302769>>1302791A cycle in sleep (4 stages of NREM and a final of REM) usually occurs in a 90 minute interval, so as long as you wake up while not interrupting a cycle, and you've gotten a minimum amount of total sleep, you're fine.
So six hours (4 multiples of the 1:30 cycle)
and what most people consider eight hours (actually 7:30, so a multiple of 5 of the 1:30 cycle) are both fine.
Just don't alarm and break the middle of your cycle and you're fine.