A home renovation is an investment, both in terms of time and finances. You’ll be spending a lot of both—especially since you’ll more or less be renovating your whole home—so you need to be sure you’re ready to commit.

On top of coordinating schedules, checking samples, selecting materials, and ordering supplies, you’re going to have to keep track of your financial plan and your current living situation, too. All this doesn’t take away from how rewarding a whole house renovation can be, of course. But a little help certainly goes a long way to ensuring a smooth, stress-free execution.

We’ve rounded up the top three most common—and most costly—mistakes to avoid during your home renovation.

1. Mistaking “Quote” as “Final Price”

For homeowners who have never experienced a whole home renovation before, the overall cost of the project can be a little alarming—if you took the contractor’s “quote” to mean “final price.”

As much as we hate to admit it, a quote is not as accurate as we’d like it to be. It’s the best guess of a professional contractor of what the whole renovation will cost all in all, accounting for several factors like materials, labor, documentation, and so on. These prices are pulled and calculated based on the professional’s industry knowledge and personal experience.

However, it is still a (highly) educated estimate. It is not uncommon or unheard of for the final price to be a couple hundred to a couple thousand dollars higher than the quoted price.

What does this mean? Don’t base your home renovation’s financial plan on the price you’re quoted. Give yourself ample wiggle room for unexpected add-ons, rush orders, last-minute changes, and other similar events that could hike up the price. Some projects may end up costing twice as much as what you’re quoted.

(Of course, the opposite does happen from time to time, but very rarely will you end up paying less than the quoted price for a whole home renovation).

You also need to be as detailed as possible when requesting a quote. Different contractors will have different formulas for estimating a project’s price, which means you can get two vastly different quotes for the same home improvement project. So be sure to tell them exactly what you want included in the quote; like materials, labor, wiring, and so on.

2. Focusing on Aesthetics Too Much

Common Mistakes to Avoid During a Whole House 1We totally get it; real hardwood floors just feel and sound richer compared to their vinyl dupes. Outlets along the wall can totally disrupt the minimalist vibe. And a regular staircase takes up too much space, whereas a spiral one looks effortlessly elegant and takes up half as much room.

A lot of homeowners name aesthetics as one of the biggest reasons behind their whole home renovation. Whether it’s breathing new life into an old home with a fresh coat of paint or knocking down that wall to create a gorgeous open floor plan, home improvement can be heavily driven by fashion and visual preference.

However, many homeowners that sacrifice form for function eventually end up regretting their decision.

What does this mean? Visuals are short-lived. Comfort is long-term.

When you’re undertaking a whole home renovation, it’s important to look at the space you have and seriously consider how you’ll live in that space. Is this space supposed to be comforting? Utilitarian? Private? Public?

Considering form before function can affect all these tiny details—floor placement, window angles, type of furniture, and so on—that will, ultimately, make your home more livable. You don’t want to spend a whole chunk of cash on uncomfortable leather couches or real hardwood floors just to be burdened by the discomfort of upkeep further down the line.

And don’t worry about being trendy or up-to-date. Opt for versatility instead.

3. Ignoring the Plan

When it comes to whole house renovation, having a clear, concise construction/renovation plan can eliminate so many unknowns: cost, timeline, materials, finished product. It is incredibly important that you, as the homeowner, have a long, detailed talk with your contractor about what you want to achieve. From this, any professional home contractor can create a comprehensive plan of action that serves as a blueprint, guide, and cheat sheet—all in one.

Unfortunately, a lot of homeowners—and even some contractors—don’t treat the plan as seriously as they should. In the middle of renovations, the homeowner might suddenly decide to change this section, or ask if they can add on to that section. And what’s worse? The contractors often follow these impulse-driven changes.

So what happens?

Materials get reordered, existing supplies need to be returned or stored, and more professionals are called in for consultation and/or labor.

Related Content: Home Remodeling: 5 Reasons a Whole House Design Guide is a Must-Have

What does this mean? It’s important you know that even the slightest of changes can have a huge impact on the overall project cost and timeline. Something as simple as changing the finish can push the timeline back another one to two days while people wait for the new supplies to be shipped in.

Treat your plan as gospel and never stray from it unless you absolutely must. The contractor comes down with the flu, the furniture you want is out of stock, or the supplies shipment gets delayed—fine. These are all perfectly reasonable—and uncontrollable—circumstances that warrant a bit of freestyling. But otherwise, stick to the plan.

Above all, the best piece of advice we can give you is to stay calm. Yes, a home renovation can be stressful and time-consuming. Yes, you’re probably going to encounter some sort of problem at some point during the process. And yes; regret might set in during a particularly rough time. But we promise, that regret will be short-lived.

Just find a reputable home contractor you can trust, be open to suggestion, insist on constant communication, and trust that things will work out—as they always do.