The mistake iPhone Duo buyers can easily avoid

The iPhone Duo is costly, and fixing it comes at a high price as well.

The iPhone Duo is finally available, and you might be interested in one after reading reviews. There can be some justification for its mighty $2,000 price tag if you see it as combining an iPhone with an iPad mini. If you want to be a little more productive on the go when you don't have your laptop, here's your answer. It should also be a killer ereader and media player.

With such a high barrier to entry, it can be tempting to skip iPhone Duo add-ons of the sort you'd normally pick up alongside a new phone. You probably already have enough cables and chargers. Heck, you might even think to skip a case if you're careful about how you hold and stash your new foldable.

One extra you probably shouldn't dodge, though, is AppleCare+ or AppleCare One. While it adds hundreds of dollars to your phone's lifetime price, the penalty if something goes wrong could be even more severe. It's inherent to the nature of foldable phones.

A hazy screen transition on the Night Sky version of the iPhone Duo, shown in a store.

Why AppleCare could save your hide with the iPhone Duo

With a foldable phone, there's a whole extra screen to break, and the out-of-warranty repair costs for that can be astronomical. While the outer display is only 5.4 inches, service estimates suggest a repair cost of $379 for it. The main attraction — that 7.6-inch, nano-textured inner screen — is listed at $999 for repairs. That's more than many standard smartphones or tablets.

As if that weren't enough, there's at least a $199 charge for repairing the back glass, while battery service and fixing the rear cameras are $229 apiece. There's also a blanket $1,499 cost for "other damage." Presumably, that's for the hinge, bending damage or anything involving the internal components such as storage and processors.

Conversely, AppleCare+ is $20 per month or $200 annually, while AppleCare One is $20 per month for individuals or $50 per month for families. If you already have an AppleCare One family plan, or an individual plan with an older iPhone you're replacing, your new Duo might be covered at no additional cost. Otherwise, you're looking at either $400 or $480 for two years.

Before reduced AppleCare service fees, which range from $19 for cover layer fixes to $99 for other damage, those subscriptions are less than half the cost of repairing the inner display. Remember that AppleCare+ also covers theft and loss (with a $149 fee), not just accidents. That ongoing expense could save you another way if you're a frequent traveler.

The outside of a fully-open iPhone Duo clad in Apple's Navy Blue case.

Could you get away with just an iPhone Duo case?

If your only major concern is dropping your Duo, then possibly. Many cases add a raised edge around the displays and the camera bump, allowing them to absorb some impact before the force is transferred to anything vulnerable. It's also worth noting that the front display uses toughened glass materials. It's not invincible, but with a case, many drops can be survived. On top of that, the Duo features reinforced back glass, plus a metal frame and hinge cover.

The problem, once again, is that inner display. Because it needs to bend, there's no equivalent heavy-duty protective glass layer. You could thus be in serious trouble if you drop your phone when it's completely open. Hinge durability and nano-texture surface resistance against fingernails and debris also remain points of caution.

Compounded with risks like theft and loss, it's hard to ignore the peace of mind extended AppleCare brings, making it a virtual necessity. If the added costs sound too pricey, you might be better off skipping the foldable device entirely, as forking out another $2,000 for a replacement is likely not feasible for most buyers.