When it comes to managing your money, the best way to make informed, smart decisions to secure a solid financial future is to become knowledgeable about everything from credit cards to mortgages and everything in between.

After all, knowledge is power, and what you don’t know – like some of these things below, could be costing you.

What are the consequences of paying bills late?

So, you can’t seem to pay your bills on time. What difference does it make? You’ll just be up against a few late fees and maybe some penalties, right? Wrong! Given that your payment history (something that banks and issuers consider when evaluating your credit risk) accounts for 35 percent of your credit score, late payments are damaging.

How damaging?  Just one late payment – from parking tickets to medical bills – can drop your score by 100 points or more. Repeated late payments (hence, a pattern!) have a more significant impact even if you are late by only a few days each time.

Bad credit results in higher interest rates (these days, you need a score of 740 or higher to get the best rates, according to Zillow analysis) and difficulty obtaining loans altogether. Get organized!

When it comes to student loans, do you know whether you’ve chosen the right repayment plan?

Despite the dizzying array of repayment options, most student loan borrowers pick the repayment plan that costs them the least amount of money each month. And that’s the costliest in terms of interest paid over the life of the loan.

Sure, everyone has their own priorities in terms of how they spend and save money, but if you can swing it, go with the standard 10-year repayment plan.

This plan breaks down your loan balance into fixed monthly payments of at least $50 for up to 10 years. Compared to other plans, it is going to cost you the most per month (so make sure it’s budgeted for), but you’ll pay off your loan faster, and save more in interest, too.

Any idea the total cost of home ownership?

Typically, house hunters fixate on the monthly mortgage payment when they’re thinking about buying.  If they can make that payment, then they can afford the house, right? Not so fast.

There are all sorts of other costs associated with home ownership — from property taxes to maintenance fees and common charges to repairs.  And it adds up.

What does your income look like against these costs? Understand that your housing costs, in totality, should be no more than 25 to 28 percent of your monthly income.

If you’re over these percentages, but are creditworthy, you can shrink your monthly costs by making a larger down payment. The standard or most popular option across the country is 20 percent, but in certain markets like New York City, the typical down payment is 25% of the home’s value, according to StreetEasy analysis. Plan accordingly.

How much do you think you’ll need to live comfortably in retirement?

Most Americans have no idea how much they need to save for retirement in order to live comfortably in retirement because they’ve never run the numbers! Go to Choose to Save to get a ballpark estimate.

And keep in mind that as a general rule of thumb, you’re going to need about eight times your ending salary to live comfortably in retirement (although there are a lot of variables that can change that, such as unexpected medical costs).

Start saving now! How? The best strategy is to have someone else save for you, with your employer or your bank automatically taking money off the top of your paycheck. While it’s often recommended that you try to set aside 10 percent of your income for retirement — or 15 percent including any employer match, you can start with much smaller amounts. The important thing is to get into the habit. And when you don’t see the money in the first place, you won’t miss it.