What is the difference between requerir and exigir?

Question

I believe that they both mean to "require." But do they refer to different "degrees" (urgencies) or types of requirments?

Can they be used interchangeably or is one more suitable in some contexts and the other more suitable in other contexts?

Answer 1

You're right both mean mean to require in a certain way, acording to RAE one of the meanings of requerir is necesitar (to need), the way I've seen it being used is when asking for something or stating a need, but in a way like "requesting", while exigir (according to RAE) is more "urgent" or "strong" if you will, like demanding/commanding or giving an order. Sometimes both can be used in the same context, but you could say requerir is softer/more polite (and if it's to used in casual conversation, should be preferred if you're not too familiar with the other person) so you should use it in situations where you are requesting, while exigir should be used when you're demanding something (often with a certain authoritarian sense).

Answer 2

Requerir is used more on an context where the subjects wants or needs something but is not neccesaraly mandatory. Exigir is most likely used when the subject demands something.

Requiero unas vacaciones: I need some vacations.

Exijo una explicación: I demand an explanation.