While regex is probably the better way to handle this scenario, it isn't necessary. You can search and replace regular space characters just as well as any other character (as you've discovered in your own regex). I have a couple of old simple macros that do just that:
If you do want to use regex though, I would suggest just searching for \s+, as that will replace any number of white-space characters in your text (with your current search pattern, a mistyped double space will result in hello- world).
And as a newcomer to regex myself, I would encourage you to push yourself to learn and use it more. My own understanding is still rudimentary, yet even so it's still proven immensely useful.