> Plastic (debit or credit) lets you spend more than you should.

I think this differs from person to person. Cash for me requires more self-discipline, because I don't automatically get a log of where the money has gone and so in some ways it just disappears without me having an idea where

(Sure, my bank statement can't tell me what I bought at a given shop, but knowing I spent €X at a shop is a good memory jog)