Home Depot peddles its put-it-together-yourself pergola kits like crazy. ThisOldHouse.com is home to dozens of videos that teach inexperienced homeowners how to do everything from hanging drywall to laying a brick pathway. And then there are the scads of TV shows that put homeowners to task upending and redecorating their homes. All this might have you wondering … to DIY or not to DIY?

God’s honest truth is that while the Do It Yourself approach appeals to lots of ambitious weekend warrior types, there are plenty of projects best left to the pros … lest you make a mistake that will bug you forever–or worse, cost you lots of $$ to redo. (By the way, there’s a TV show for that, too; HGTV is launching its series Over Your Head, featuring hapless homeowners who tore up their kitchen or bathroom and now can’t put the pieces back together again.) In my many years of work inside and outside of homes, I gotta say that I’ve seen some horrendous DIY jobs that will stick with me forever. Which leads me to warn: You may want to leave the following projects to a professional …

Kitchen and bath remodels. The plumbing, the cabinet hanging, the installation of tile backsplashes and costly appliances–it’s all too tricky for the average Joe or Jane. (I’ve seen enough crooked countertops to last me a lifetime.) And considering the indisputable fact that a good kitchen will sell a house in a heartbeat, it’s a better investment to have your kitchen done especially well. This is not the place to try to save yourself a few bones. Same goes for the bathroom. A janky bathroom is just about the biggest turn-off to a potential home buyer. Plus, you aren’t going to want to put your bathroom out of commission for very long since you, ya know, need it when mother nature calls and all.

Window installation. Whatever you do, don’t try your hand at window installation. This is one job that you don’t want to be messy around the edges. Not only do you want your windows to be installed securely but you also want them to maximize your energy savings. It’s too easy for someone inexperienced to take incorrect measurements and leave themselves with the problem of how to patch a too-big hole in the side of their house.

Floor installation. There are lots of rookie mistakes that are easy to make when it comes to putting in your own floors. Chief among these mistakes is not letting that pile of hardwood flooring planks you just bought acclimate to the temperature and humidity in your home. Patience is the name of this game, as it’s recommended that hardwood flooring acclimate for an average of five days before installion to protect it from expanding and contracting during the different seasons. Laminate flooring can be equally tricky, with lots of DIY jobs resulting in unsightly seams.

Let me know if you have questions about whether or not to tackle a job yourself. I’ll be happy to shoot straight with you.