Sometimes you don’t want to deal with the hassle of hiring a contractor for a home renovation project. Perhaps you think the job is so small, you can get it done quicker and cheaper on your own.

While some DIY projects are definitely feasible, you can make costly mistakes, and fixing them can end up costing more than going to a professional in the first place. When tackling a DIY project, keep the following do’s and don’ts in mind.

Do: Measure Everything

Incorrect measurements are a tiny problem that can have catastrophic results. There’s nothing worse than getting your new countertop into your home, only to realize that it’s an inch short on either end, or that the new window you picked out ends up too wide for the wall.

By paying attention to detail and taking down as precise of measurements as you possibly can, you can save yourself a lot of hassle and dealing with returns along the way.

Don’t: Ignore Safety

Just because you think you can handle something doesn’t mean you should. Accidentally injuring yourself during a renovation project can prove not only very dangerous, but very costly. Hospital stays and urgent care visits can quickly add up to be more than the cost of the project you were trying to complete.

Use a proper, sturdy ladder to reach tall places; be cautious with power tools and wear eye protection when necessary; don’t move heavy objects on your own.

Do: Floors First

If you’re redoing a whole room, it may be tempting to get that gorgeous shade of paint you picked out onto the walls. But you’ll save yourself a lot of trouble and cleaning if you get the floors done first.

Replacing flooring can scuff the walls and baseboards, so get it out of the way from the get-go and then tackle the rest of the room. Remember to carefully cover and protect your new flooring when you move on to everything else.

Don’t: Skip the Primer

Priming before painting may seem like a step you can skip if you’re repainting on a budget or time crunch. But a good coat of primer can ensure your new paint job lasts longer and stays brighter, as well as help it stand up to wear.

Primer will cover any imperfections on the surface and provide a better surface for the paint to stick to. It also can help block out stains and odors.

Do: Take Pictures Through the Process

This may seem frivolous to some, but taking periodic snapshots of the progress of your work can actually be a helpful thing. Documenting each step as you work can help you identify where problems arose, or serve as a reminder of where you are in the process as you consider next steps. Plus, having some clear before-and-after shots is incredibly satisfying.

Don’t: Toss the Receipts

Especially when making big changes like adding solar panels or a new air conditioning unit, keep the receipts for each expense from your renovation somewhere you can find them later.

If you decide to sell your home, you can get some tax deductions from them that year.

Some improvements can cash in on the energy-saving credit, and certain additions can be counted as medical expenses if the improvement is considered medically necessary.

Do: When in Doubt, Hire a Pro

Remember that you don’t have to tackle anything you feel unprepared to handle. There’s a reason these people are professionals—they’ve been trained to do the job you need, and to do it safely and correctly. If you have any doubt, go with a pro.

Completing an improvement to your home on your own can be a great source of pride, so make sure you take all the steps necessary to get the job done right.