When you work on a complex part just turn it on from time to time, do a CTRL+Q and, if everything is fine, turn it off again.
When modeling complex parts, I'd turn it on – and leave it on all the time.
From the moment you start experiencing performance issues, then you can make a choice to turn it off.
We all have different pain levels and different things that cause us pain. I dislike waiting for the computer to finish a feature for me, so I leave VOR off. In theory, I should check my parts periodically, but I tend to forget. Then, when my part goes bad, I have to work harder to figure out where it went bad. Other people would rather wait for the computer to complete the features, but know that their model is good.
Choose your poison!