If you are using :make, and _don't_ jump out of the file (split the window if you need to jump out), line deletions and additions down the window are automatically accounted for.
As for turning it on or off, I've never had too, unless it's part of cindent.
Use the :make command so that vim knows about the errors. Then use :clist to list errors, :cnext to go to the next error, etc. :help clist and :help make will get you started.
As for turning it on or off, I've never had too, unless it's part of cindent.