For some reason, when it comes to outdated gadgets, some people have a hard time letting go. It's never a great idea to make sweeping generalisations, but for now let's call this group "old people".
Old people, quite naturally, can maintain strong emotional attachments to what was once cutting-edge technologies, if only because the exorbitant price they had to pay for them remains seared into their memories.
Back in 1976, I remember tagging along with my mum and older brother on four separate trips to different stores before she was finally willing to pay US$50 (the equivalent of $200 in 2011) for his first hand-held calculator.
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She picked a good one, though. How do I know? When I visited her last year she was still using it to calculate her taxes. It works at least as well as the tiny one now dangling from my key chain that was so cheap I don't even remember buying it (maybe someone gave it to me?).
Likewise, music lovers with at least some grey around the temples can no doubt relate to my mum's pain. From vinyl to 8-tracks to MP3s, keeping up with music has required more costume changes than a Lady GaGa concert. What we could use is the semblance, at least, of a break from this frenetic pace of change.
Fortunately, AirCassette (Dh7.3; iPhone, iPod) knows just what we need - some old-fashioned patronising. This app turns your smartphone screen into a realistic-looking, spinning cassette player while you listen to your music, complete with what looks like handwritten labels of the artist and song that's playing from your 21st-century music library.
You can choose from a selection of about half a dozen cassette- tape designs. And while AirCasette offers a very realistic walk down memory lane (complete with animations for rewind and fast-forward), it also hides some somewhat cool digital-age features under the hood - it allows you to share links to the songs you're listening to through the iTunes store or, for that matter, your entire song list.
One simple swipe will take you to a more 21st-century interface that lets you choose your songs. You can also turn your playlists into "mixed tapes".
For those who long for the days when they could go to the movies without hearing phones ring or just walk into a friend's house and understand his remote control, AirCassette will stir pleasant memories of such simpler times.
And anyone who's ever had to pay $50 for a calculator deserves that, at least.
Have some great personal finance apps that you want to share? Write to Curt Brandao at email@example.com