You finally get your new foldable. You take it out of the box, unfold it, admire how ridiculously thin it is, and wonder how they managed to cram an entire tablet into something that fits in your pocket. Then you put a giant case on it. And just like that, your sleek new foldable becomes a brick.

That doesn't mean thick cases are bad. If you're carrying around a phone that costs well over $1,000, wanting serious protection is completely reasonable. But cases affect foldables differently than they do regular phones, and thickness is something you should actually think about before buying one.

You're putting a case on both sides of your phone

This sounds obvious, but it's easy to overlook.

A regular phone gets one shell around it. A foldable basically gets two.

When the phone is closed, the thickness added to the front and back of the device stacks together. A case that doesn't look particularly bulky in product photos can feel very different once it's installed and the phone is folded shut.

That's why a couple of millimeters can matter so much more here.

Foldable manufacturers have spent years shaving weight and thickness from these phones. The latest models finally feel less like two phones taped together and more like something you can comfortably carry every day. A bulky case can undo a surprising amount of that progress.

Weight matters too

Thickness isn't the only thing you're adding.

Foldables already tend to be heavier than regular phones. Add a big protective case, hinge protection, a magnetic ring, a kickstand or some combination of those things, and you'll notice the extra weight pretty quickly.

That doesn't necessarily matter if maximum protection is your priority. For some people, knowing their hinge and corners are covered is worth every extra gram.

But if one of the reasons you bought a newer foldable was because it finally felt thinner and lighter, it's worth checking how much your case weighs before covering it up.

The front screen changes everything

This is one of those things that's hard to understand until you've actually used a foldable with a case. The front half of a foldable case has to wrap around the cover display. Depending on the case, that can create a noticeable raised edge around an already narrow screen.

Suddenly swiping from the edge doesn't feel quite as natural. Gestures can be harder to hit. Even normal scrolling can feel different when your finger keeps running into the side of the case. Some people won't care at all.

Others will take the case off after a week because it drives them crazy.

It's also one of the reasons extremely thin cases have become so popular with foldable owners. Sometimes the difference isn't how the phone looks. It's how much the case stays out of your way.

Then there's the hinge

Here's where things get complicated.

Hinge protection makes sense. The hinge is one of the most important parts of a foldable, and leaving it exposed can feel a little terrifying on a phone this expensive. The problem is that protecting it usually requires adding more material.

Some cases use a large cover over the hinge. Others use smaller mechanisms that move as the phone opens and closes. Either way, you're usually trading some of that slim feel for more coverage.

There isn't a right answer here.

If you work outside, drop your phone regularly or just don't want to worry about it, the extra protection may be completely worth it. If your phone spends most of its life on a desk, in your hand or in a relatively safe pocket, you might decide that you don't need to turn it into a tank. That's the tradeoff.

Thin doesn't mean useless

There's also a tendency to treat case protection like there are only two choices: giant protective case or basically nothing. There's a lot in between.

A thin case can give you more grip, protect the back and sides from scratches and keep the phone from making direct contact with every surface you put it on.

Some people aren't even looking for serious drop protection. They just want their very expensive and very slippery phone to feel a little safer in their hand.

That's a perfectly legitimate reason to use a case. Just understand what you're buying. An ultra thin aramid case isn't going to provide the same protection as a thick case with reinforced corners and a covered hinge. No amount of marketing changes that. You're choosing less protection in exchange for less bulk.

So how thin should you go?

That depends on you.

If you've dropped your last three phones onto concrete, maybe this isn't the place to chase the thinnest case you can find.

If you're careful with your phones and hate bulky cases, wrapping your foldable in the biggest case available just because it technically offers more protection probably isn't going to make you happy either.

There are also plenty of people who split the difference. They use a thin case for grip and everyday scratches, then rely on device insurance for the catastrophic stuff. Others want every corner and the entire hinge covered. Some brave souls use no case at all.

We're not here to tell you which camp you're supposed to join.

We just think thickness deserves a spot on the checklist when you're shopping for a foldable case. Look at the weight. Look at whether the hinge is covered. Pay attention to the lip around the cover screen. Think about how much bulk is being added when the phone is closed, not just how the case looks when it's unfolded.

Because the most protective case isn't automatically the best case.

The best one is the case that gives you enough protection without taking away the things you liked about your foldable in the first place.

After all, you bought a foldable. You probably don't want to carry a brick.