Many of us jailbreakers know how frustrating it can be to debug the modifications we make to iOS. When installing an app in Cydia, if the app requires it, Cydia gives you a prompt to restart your springboard.
There are two types of restarts you can have on your iPhone: a hardware restart and a software restart. A hardware restart takes considerably longer, and it is when you see the Apple boot logo (or your own, modded logo). A simple software restart usually does the trick for installing new packages on your iPhone, and it also helps with ironing out the bugs you may be experiencing...