Main difference between Library and Helper?

[eluser]Jelmer[/eluser]
To be honest I don't really know, if it's a set of functions I prefer to use a library - especially if I need DB access (even though I have to load the CI superobject the same as if it where a helper).

The point about the amount of code I never considered an upside, because the extra code $this->library helps me remember where the function comes from - which is sometimes usefull if you load helpers/libraries in the class constructor or from autoload. Also it keeps the general namespace clean, though I must admit I never really cared about that...