You can also do the same for spending - you work out your "real" income, how long it takes to earn enough money to spend on the thing you want, and determine if it's worth working that hard to spend the money.
I have conditioned myself to do that years ago.
I think - in hindsight - it can be dangerous, because then you start to over-analyse every cent you spend on anything.
I find myself doing things such as; I'm out somewhere and I feel thirsty, and could easily go into a shop and buy a bottle of water, or a softdrink, etc.
But then I start to look at what they charge for one, (we used to sell drinks in my Proshops and I know what the wholesale cost is), plus the opportunity cost of that drink as opposed to other more important items I need in my life right now....
So, I end up not buying the drink, and either wait until I get home, or find a tap somewhere.
Same with food; I'm very reluctant to buy anything take-away when I am by myself...I wait until I get home if it's not that far away until I get there.
Pretty sad mindset - good for the aspiring property investor with no money, though.