My jailbroken iPod touch 4G (4.3.3., I think) has been acting up for a few months already, and it's getting worse. Apps often close themselves randomly. After a respring (which I'm paranoid about, always fearing something might go wrong, even if it shouldn't), things are back to normal for a little while - I can open and use huge apps like Keynote, or browse the web without Safari closing all the time. After a while of using the device, it goes back to "normal", closing the open app shortly after it's opened. "Closed" means the screen turns black for a few seconds, then it goes back to Springboard. Lately, even the Music app sometimes closes mid-song. Animations like opening or closing apps are usually jerky or get skipped altogether, or only like the second half of them is played. Scrolling through Springboard pages feels laggy, too, and it takes a few seconds for an app to be closed by the home button, or a folder or the multitasking tray to open, which also happens in a laggy way. SBSettings usually says I have below 30MB of available memory, and after an app crashes it's between nine and eleven megabytes. I think it might be something jailbreak-related. I could give you a list of all my MS extensions and all that, if that helps. TL;DR iPod touch turned laggy and slow, runs out of memory, apps crash; likely a jailbreak related issue.