I never hear them.
No, I'm not deaf. I spend most of the day either in an office, or in meetings and calls. The eruption of Alan Rickman's phenomenal quote during a conference call tends to sidetrack the conversation, so I keep the phone on mute. My carefully selected ringtones are reduced to a simple buzz, as my phone quietly vibrates, and I am left to wonder if the message is about a nearby special, or something more critical. Sigh.
Vibrafications. Now, I can add a custom vibration pattern to each person, whether they text or call, so I instantly know who is trying to reach me. Yes, Android has this as an app, but the tight grip of Apple prevents such things. But with $3 and jailbreaking, you get the best solution for a world that can gladly do without the Led Zeppelin riffs of my brother-in-law checking on dinner plans. Great app, great developer, and a great solution that, frankly, Apple should have done.
It's easy to set up, and you can preview each vibration pattern. You can set different patterns for each person, or even different patterns for the same person via different methods. Still want your ringtones, but you want custom patterns when the phone is not on mute? Check. How about if the person emails you? You bet.
This is the kind of app that Android encourages and Apple needs to encourage, not restrict, in order to hold on to that commanding market share. As for me, it's another great reminder why I am delighted I jailbroke, and will stay as such.