I can’t recall how many times that I have to reselect the visual selection again just because I never seem to remember, from help:

gv
Start Visual mode with the same area as the previous area and the same mode. In Visual mode the current and the previous Visual area are exchanged. After using p or P in Visual mode the text that was put will be selected.

Usually, that happened when I indented a block then needed to do some text replacements; others like my regular expressions got wrong and the selection was already unselected.

The very first time I was made aware of gv was by A Tale of Two Selections (2014-02-14). It’s been more than a year and I still couldn’t remember it, even it’d be very helpful.

Hopefully, I will remember it from now on.