When you buy things using your credit card, it's sometimes easy to lose track of how much money you have spent on it so far for the month, as long as you haven't reached your credit limit. You may see the latest Apple (AAPL) gadget ('I must have that iPad!!') or that nice pair of shoes, and go weak in the knees. But luckily, you've got a credit card! Now, credit cards are really a necessity and huge convenience to have in this day and age, but if you aren't careful and fall prey to overspending on your credit card, that could get you into serious debt.

Do you have a habit of spending unnecessarily without thinking about the consequences? If that's the case, I have a simple solution for you.

From now on, in order to control your spending, you must start looking at your money in relation to the time it took you to earn it. In practical terms, it would mean to:

1. Find out how much money you earn after paying taxes.

Let's say that you earn $4,000 a month and that your federal taxes are 25% of your income. To find out how much money you earn after paying taxes, first you have to calculate how much you have to pay in taxes, which would be: 25/100 x 4000 = $1,000. This is the amount of taxes you have to pay each month. To know how much money you take home after taxes, all you've got to do is subtract the amount of taxes from your monthly salary, which would be $4,000-$1,000=$3,000.

2. Divide the amount of money you earn after taxes by the number of hours you work.

Using the above example, what you would have to do now is calculate first of all the amount of hours you work every month. Let's say you work 8 hours a day 5 days a week, and there are 4 weeks in a month, so you have 8x5x4=160 working hours a month.

What you're going to do now is divide $3,000 by 160 to find out how much money you earn every hour:  $3,000/160=$18.75. In this case, you earn about $19 per hour.

3. When purchasing something, compare the money you're spending to the amount of time it took you to accumulate that amount, and see it it's worth it.

Let's say you eat out in restaurants frequently, paying from $50 to $80 on a meal for yourself. That would mean that you are spending the money you earn for 3-4 hours of work each time you eat out.

Is it worth it to spend the money that has taken you 3-4 hours to earn on a meal every few days? Now that is the question only you yourself can answer.

The point I'm bringing across here is that if you do these simple calculations each time you buy things and figure out how much of your time you've put into making the money you're about to spend, you will have a better idea of whether it's worth it or not to spend on the things that you want.

If you adopt this mindset when it comes to spending, it will give you a clearer perspective of how you want to prioritize your spending. When you stop overspending, you are less likely to chalk up debt on your credit cards and more able to put aside some savings every month.