Some editors have “Perl Tidy” tools that will automatically reformat source-code without changing it, in order to improve visual consistency within the code.   Yes, such changes can be a big improvement, because we are extremely visual creatures.

One thing can be a problem, though ... if you reformat an entire module, a source code control system will perceive that the entire module has been changed.   Therefore, what I often prefer to do is to highlight a particular block of code, reformat it automatically, then check-in the file with an appropriate comment.   Then, separately, make the changes that I am contemplating, and check those in again.   This creates a much clearer history of what was changed and why.   Gradually, over the course of time, but only in the areas currently receiving attention for other reasons, the visual quality of the code will improve.