How much have you grinded for one pice of glamor?

[Iscah]

There are still dungeon drops I've never been able to get. The current loot system was not put in place until ShB, so in dungeons prior to then it is total RNG.

It has nothing to do with when the dungeon was released (besides the ARR dungeons not having the guaranteed drop prior to their loot overhaul in 5.3). All levelling dungeons have a guaranteed piece; all level 50, 60, 70, 80, 90 dungeons do not.