When to encode space to plus (+) or ?

Question

Sometimes the spaces get URL encoded to the + sign, some other times to %20. What is the difference and why should this happen?

Answer 1

What's the difference: See other answers.

When use + instead of %20? Use + if, for some reason, you want to make the URL query string (?.....) or hash fragment (#....) more readable. Example: You can actually read this:

https://www.google.se/#q=google+doesn%27t+encode+:+and+uses+%2B+instead+of+spaces (%2B = +)

But the following is a lot harder to read: (at least to me)

https://www.google.se/#q=google%20doesn%27t%20oops%20:%20%20this%20text%20%2B%20is%20different%20spaces

I would think + is unlikely to break anything, since Google uses + (see the 1st link above) and they've probably thought about this. I'm going to use + myself just because readable + Google thinks it's OK.