You’re paying way, way too much to get a little more space on your iPad and iPhone.

Apple and other device makers probably recognize this as well. They’re making a lot of money from jacking up the price of storage now, but that party can’t last forever. For one thing, as Rassweiler points out, the cost of Flash memory is sliding. Earlier this year, Apple acquired Anobit, a startup that will likely reduce storage prices even further. (One theory is that Anobit’s technology will allow Apple to cram more data on each Flash chip, letting it make a 24GB iPad with a 16GB chip.) Today, Flash memory chips cost about $1 per gigabyte, but as tech improvements slash these prices, Apple and its rivals will feel pressure to bump up the base level of storage. Once that happens—if Apple’s entry-level iPad offers 24GB or 32GB—upgrading will become even less attractive, especially if broadband networks and cloud-enabled apps keep improving.

You should keep this future in mind when you’re at the Apple Store. How long are you going to keep your new iPad, anyway? Better phones and tablets come out every year. The one you’re buying now isn’t going to be with you forever. At best, you’ll get three years out of it before it becomes obsolete. Modern gadgets are meant to be disposable machines, not eternal repositories of all your stuff. So buy just as much as you need—and if you find yourself running out of room someday, well, Apple will be happy to take your money for whatever it’s peddling then.