talking about focus hacks…when at uni I had odd studying hours, often mixing day and night without any clear distinction.

What kept me grounded were scented candles. IKEA used to sell those with an expected burning time. My favs were the 40hrs ones [0]. My exam preparation was 1 candle for revising notes, 1 candle to go through relevant books and 1-2 candles to do exercises (exp for calculus and similar courses). Add 1 more for the final revision. I was constantly lighting on and off those.

[0] https://www.ikea.com/gb/en/p/jaemlik-scented-candle-in-glass...