SoBrief makes a good job summarising books:
For me, the best hack is having no alarm clock and waking up naturally (ie a the end of sleep cycle). This simple rule changed my life.
no alarm clock is amazing, although sadly in my case i have to get up at 6am to get the kids to school, it;s absolute shit. luckily we have a long 3 month summer break when with no alarm clocks
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