It takes too long :/ but it has better quality

I think there are more factors to decide on whether to use 2 pass rendering, I use x264 encoder for rendering (can't use hardware since it sucks)
 

This is a general question so no specs or video properties, no yes or no, just what factors should be taken in mind and what one needs to know to decide whether to use it or not, like a tutorial, I am searching for answers but it doesn't really help to not get an explanation or at least some small details