For those who give a shit about privacy, consider the linked past post. The ATM reads the serial numbers of banknotes as it’s dispensed and later used to track your habits.

So to mitigate the threat of unwarranted mass surveillance, it’s a good idea to put your ATM withdrawals in an envelope with the transaction date. Then let it sit in your safe for 6—12 months so the tracking data becomes stale before you actually use it. A good length of time suggests the banknotes went through many hands before they are back on the radar.