Should I use spaces around an en-dash?

The en-dash (–) is narrower than the em dash (—) and wider than the hyphen (-). In US English, you should never have spaces around an en-dash. If you think you should be using spaces then maybe you should be using an em-dash instead.

The en-dash is used for:

i) A span or range of numbers, e.g. See chapters 10–12.

ii) A score, e.g. We won the match 3–1.

iii) Linking two place names, e.g. The Calais–Dover ferry.