When I was first learning to drive, my parents always told me to round off the price at the gas pump. If the pump clicked at $21.89, I always tried to pump just enough to try to get it to exactly $22.00. This of course was to make it easy to pay with exact change. Even years later I would always try to round it off and always get irritated with myself if I got even one cent over. Then there were the days you knew I was having an off day when my total was $40.03 or higher.
One day after this happened I found myself mentally scolding myself for not hitting the mark perfectly and going over a penny or two. But then I had a realization. I wasn't even paying with cash, so why did it really matter if my total was exactly $40.00? Did it matter if it was $40.16 or even $40.73? Does the total effect the way my debit card swipes? Not in the slightest.
Additionally, the way I log my purchases with Excel makes it easy to Ctrl + F to find any purchase I've made in recent months. But if every time I fill up gas it is exactly $40.00, I would still have to wade through purchases to find the right one I'm looking for. But if one week a gas purchase is $40.16 and the next $40.73, it's much less likely there is a duplicate and makes my system that much easier. You see, the way my parents have always done things in this case was not the best way for me. Yet for years I did it that way just because it was the way I was taught.
What about you? Are there things you do on a regular basis that you're not even sure why you do? Are there things you could cut out of your schedule or customize to better fit your needs?