Anyone who has built a home knows how quickly that attractive base price can start climbing once you walk into the design center. The model home you walked through and fell in love with generally isn’t the base model. It’s the base model after someone checked approximately every upgrade box available.

Once you’ve made all the upgraded choices, landed on an upgraded price and painfully waited through the build process, you finally get the keys. Congratulations! Now you need sprinklers, sod, landscaping, window coverings, fencing and maybe a deck or patio. None of those items were included in the upgrade list. Depending on the house and lot, that list can get expensive very quickly.

The bigger problem is that much of that money doesn’t immediately translate dollar for dollar into the value of the home. For example, spend $15,000 on a yard, $8,000 on blinds and another $10,000 on fencing, and you most certainly don’t have a house worth $33,000 more. However, you did just spend that money out of your own pocket.

For that reason, I would warn buyers that, for the first few years, they could end up a little upside down — not necessarily because the home’s value had dropped, but because they had substantially more money invested in the property than they could reasonably expect to get back if they had to turn around and sell it.

For a long time, that was one of the biggest arguments in favor of buying an existing home. Someone else had already paid for the fence, the sprinklers, the grass and the window coverings. In fact, most existing homes even have indoor plumbing at no extra cost.

But the market has changed. Right now, I’m having almost the opposite conversation with buyers. Existing homes are having a difficult time competing with what some builders are offering.

Builders have inventory they need to move, and they aren’t emotionally attached to it. They aren’t waiting for someone to appreciate the backsplash or hoping spring will bring the perfect buyer. They have completed homes sitting on their books, and those homes cost them money every day they don’t sell. Most larger production builders also have much deeper pockets than the average homeowner.

So they’re doing something builders haven’t always been particularly famous for doing: offering deals. Those deals can take the form of price reductions, closing-cost assistance, mortgage-rate buydowns, landscaping at no extra cost, and preferred-lender incentives. That makes new construction worth another conversation.

It also makes having your own buyer’s agent more important than ever. I am not kidding. Things can get confusing.

Builders may be offering some impressive incentives right now, but that doesn’t necessarily mean every incentive is as valuable as it sounds. Ten or twenty thousand dollars toward something certainly gets your attention. The question is where that money is going and whether that’s actually the best place to put it. Would you be better off with a lower purchase price? Closing-cost assistance? Upgrades? A permanent interest-rate buydown? Does the incentive require you to use the builder’s preferred lender? And if it does, how does that loan compare with what you could get somewhere else?

This is where having someone on your side who knows how to run the numbers matters.

The salesperson sitting in the model home may be absolutely wonderful, and plenty of them are. They may know every floor plan, lot and cabinet option available. They may also have snacks, which admittedly makes everyone seem more trustworthy. However, they work for the builder, not for you. That’s not criticism. That’s their job. Their responsibility is to sell the builder’s homes and protect the builder’s interests. Your buyer’s agent has a different job: protecting yours.

You still need to compare that shiny new home with the rest of the market, and the builder’s salesperson likely can’t help with that. Perhaps the builder is offering $20,000 in incentives, but the house is already priced $30,000 above comparable properties. Maybe the advertised interest rate is fantastic, but only under very specific financing terms. Maybe the “included upgrades” aren’t things you would have paid extra for anyway. Or maybe it really is a terrific deal. The point is, somebody should be looking at all of it, not just the monthly payment printed on the sign outside the model home.

Your agent can compare the price with nearby new construction and existing homes, look at recent sales, help evaluate lot premiums and upgrades, review what you’re actually getting for the money and negotiate where there’s room to negotiate.

Also, please don’t skip the inspection just because nobody has lived in the house yet. New does not mean flawless. Homes are still built by human beings, subcontractors, and, judging by a few things I’ve seen over the years, occasionally someone who may have been having a particularly rough Tuesday. An independent inspection gives you another set of eyes on the property before it becomes your problem.

There’s one more thing I wish every buyer knew before deciding to “just stop by” a model home. Take your agent with you — or, at the very least, talk to your agent before you go. Builder policies vary, but some require your agent to accompany you or be registered as your agent on your first visit.

So which wins, new or existing? Sometimes the existing home still does, and right now, sometimes it doesn’t. If the brand-new house comes with the right price, a lower interest rate, closing-cost help, warranties and nobody else’s mysterious carpet stains, it deserves a spot on the list.