I'm on my iPhone all throughout the day, so when an update for an app pops up, I usually grab it right away. On my iPad, however, it's a different story. Sometimes I'll go a couple of days without using it, and the updates tend to pile up.
For those of you with a similar problem, you'll be happy to hear that there's a jailbreak tweak called Auto App Updater that can automatically install your updates for you. So you'll never have to worry about installing them manually again...