So pretty much what the title says.
Starting out in Seasons do you clear your GR's to get as high as a level as fast as possible to speed level your gems? Or do you 'Slow Roll' your GR's?
Now for those that do not know what 'Slow Rolling' is in regards to Greater Rifts, it's simply clearing up to the Guardian, taking not of how long left, then porting out. Then you go and do whatever you want untill 4:30 are left in the timer, you take your portal back to the Guardian, kill him and progress your GR Key +1 level (level 1 key, to level 2...a level 2 to level 3 etc). People do this for more chances at legendaries for the minimal usage of keys.