Missing spaces between period and text in inDesign

\.\w

Should do the basic search.

But I'm sure GREP enthusiasts will come up with a more elegant solution.

I'm thinking about excluding emails or URL of the query, i.e.

Assuming new sentence always starts with Capital letter:

\.\u

Well, it's not more elegant  and still can give you a certain number of false positives (depends on actual text).

I don't know about elegance, but you don't want to have to type in the change each time. This will work as a complete Find/Change:

Find:

\.(\w)

Replace

. $1

Note: There's a space between \. and $1

Does this ever happen with question marks or exclamation marks? If so there should be a way to do it for those too. I just don't know it myself.

I guess, vinny and I just wanted to leave some space for OP's creative mind

Well, this one will insert a space after any punctuation and any character (with Change to field revealed):

Find what: ([[:punct:]])(\w)

Change to: $1 $2

And for question and exclamation marks only, a bit different approach:

Find what: [\?\!]\K\w

Change to: \s$0

Forum is incredibly laggy today, while everything other is just fine. Am I the one? Question is already marked as 'answered', but one of my (rather early) posts is still 'being moderated'

Well...

Just for comment! Not global but really less risky!

(^/)