Yeah, that and tolerance.
My parents would let us kids have a glass of Coke before we brushed our teeth and went to bed. I can now drink a cup of coffee before bed and sleep like a log.
How quickly does caffeine metabolize, anyway?
Btw: a friend recommended his podcast to me. I tried to listen, but it was so full of bullshit jargon, ads, and goop-bro woo I couldn’t make it past 30 minutes of the two hour (wtf!?) episode. On a subject that actually interested me. 
