Hitch-hiking or hitchhiking?

[Nonverbis]

The text is from Upstream proficiency by Virginia Evans and Jenny Dooley.

What troubles me is that I absolutely cannot understand when a compound word is written with a hiphen, when without one, and when we use just two separate words. Could you comment on this case: why the text gives one variant, whereas the dictionary gives another. And what is the rule?

 

[Rover_KE]

There’s no rule; both are acceptable.

The non-hyphenated version was probably written at a later date than the other. Hyphens tend to fall out of use gradually over time.

For example, at one time, to-day and to-morrow were written like that.

 

[jutfrank]

I think some people might consider the double 'h' as looking a bit awkward. The hyphenation makes the word easier to read.