Tear a car park coupon bottom-up instead of the normal top-down order; that way, even if you peel off a wrong timing, you can use it the next day/month/year!
Kinda handy for blur/sotong drivers like elinostalgia and sourcreams! Hahah
Of course, if you peeled the "Month" section wrong... you'll have to carefully plan the timing you wanna park your car on that particular date the next year (or 2/3/4 years from then when your parking coupon changes from the purple $0.50 to a yellow $4.50 one and you can park all night! Except there isn't a yellow-colored one yet)...
And yea... there isn't many places that actually require coupons nowadays anyway!
--
Actually have a few more hacks that I've thought of previously but really can't remember them off hand... hopefully I'll remember to write down my cheatsheet in the future!