In an effort to save money, many homeowners take the DIY approach to home renovations. But the truth is, a huge majority of them end up making mistakes—and those mistakes can be extremely costly.

According to a recent survey from home insurance company Clovered, 85.2 percent of homeowners surveyed named saving money as their top reason for attempting a DIY home renovation project. But 87 percent of those homeowners also said that they’ve made mistakes on DIY home projects—and those mistakes can be costly. The median amount of money spent on correcting DIY mistakes? $137.50, although that number is significantly higher for millennials, who spent $200 correcting their mistakes.

What does this mean for you? Taking a DIY approach to home renovations can potentially save money, but before you roll up your sleeves and start DIY-ing, ask yourself:

  • Do I know what I’m doing?
  • Do I have the right tools on hand?
  • Am I prepared to see this project through to completion?

If the answer to any of those questions is “no,” chances are, you’re going to make a mistake—so do yourself (and your bank account!) a favor and bring in the professionals.