The game will give you a lot of Scrolls which can take up a significant of pack space. Should you leave them behind? Or sell them? On the other hand, you never know when a particular Scroll might be useful. Should you keep them all?
You'll have to decide for yourself, of course, but here are some things for you to consider. First, there are some Scrolls that you should hold on to for special emergencies. For example, if the character you rely on to cast the Raise Dead Spell has been killed you'll want to have a Raise Dead Scroll on hand. This also applies to Resurrection, Remove Curse, Stone to Flesh, Preservation and Cure Paralysis (although there are Potions that can be used for all but the first).
As you travel to more challenging areas you will get more powerful Scrolls -- Scrolls which are usually most helpful at that level of progress through the game. Either use them at the first appropriate opportunity or sell them. If you don't, you'll soon find that you're carring around a bunch of Scrolls that are weaker than the Spells you can cast for yourself.