using print_R() and exit is just as harmful as I have cleaned up the code on production when those debug statements got released on production.
I dont say you shouln’t use them but always do something like this instead:
if (!empty($_GET['we_are_debugging'])) {
print_R('data');die()
}
with that simple check you can debug on local and production still continues to work.
That being said, your unit tests should catch it before that though
EDIT
This post has been reformatted by enclosing the code block in 3 backticks
```
on their own lines.