A habit that takes less than 5 minutes a day has made all the difference with my money

Success - in your career, relationships, or finances - starts with good habits.

It can take a while to form new ones: 66 days on average, up to 254. The good news is that some of the most valuable habits are also the simplest ones.

Consider my go-to money habit, for example: I take five minutes at the end of each day to record everything I bought.

I simply open my Excel spreadsheet, add in any purchases, and calculate the total amount I spent that day.

Every other week, I add in any income I gained, and do a quick tally of my expenses to make sure I'm on track to stay within my monthly budget. At the end of each month, I fill in my total income, tally up all of my expenses, and calculate my net savings for the month and overall year.

This five-minute routine is as effective as it is effortless, for a few reasons:

1. It allows me to notice how easily expenses can add up. You don't quite realize how quickly you can blow through cash until you start writing down each purchase. The action of recording everything provides a new awareness that keeps me in check when shopping and has helped me become more deliberate with every purchase.

2. It challenges me to lower my costs each day, week, and month. Recording expenses becomes a game, and you start to see how many days in a row you can spend $0, or under $5. You also start to dread having to record unnecessary or silly expenditures you made at the end of the day.

3. It gives me a sense of freedom when it comes to spending. For a while, I regarded nearly every expense as unnecessary or a "want" - I spent on nothing, which was impractical and limiting. With a detailed breakdown of my income and expenses in my Excel spreadsheet, I could see exactly how much money I did have to spend, and then I could determine what expenses were most important to me. I became more and more comfortable with spending on "good things," which for me, mostly meant buying quality instead of volume purchases and paying for memorable experiences.

I'm not the only one advocating this habit. A handful of everyday "millionaires next door" swear by it, it helped one family of four live comfortably off $14,000 a year, and it is highly recommended by financial adviser and bestselling author David Bach.

If you don't want to keep a spreadsheet on your computer, there are apps out there that will automatically track your expenses for you (Mint, You Need a Budget, and LearnVest are popular options), or you can write them down in a notebook.

It makes all the difference.