101+ At this point you'll start taking a penalty on quest/bonus objective experience for every level past 100. Treasures, however, remain worth their full value all the way through level 105, at which point they'll be worth something like 15% less, and then another 15% more when you ding 106. I recommend that you stop questing/gathering entirely, and collect all the treasures you can stomach, only avoiding any annoying to reach ones inside caves or behind elites/rares(where scaling does bizarro things).
Earthen Ring-Alliance-USEarthen Ring-Horde-USEcho Isles-Alliance-USEcho Isles-Horde-USEitrigg-Alliance-USEitrigg-Horde-USEldre'Thalas-Alliance-USEldre'Thalas-Horde-USElune-Alliance-USElune-Horde-USEmerald Dream-Alliance-USEmerald Dream-Horde-USEonar-Alliance-USEonar-Horde-USEredar-Alliance-USEredar-Horde-USExecutus-Alliance-USExecutus-Horde-USExodar-Alliance-USExodar-Horde-US
“The biggest struggle of overhauls like item scaling is being able to exhaustively test it,” he said. “You can’t expect any group of a few hundred people to go in and hit every piece of content that’s ever been developed over the past 15 years of World of Warcraft. That is difficult and challenging to do. What we did was listen to a lot of feedback from the PTR, what those changes looked like there. “The community is a great resource for helping us understand what we missed, and we were able to develop technology to be agile about fixing the problems very quickly in a live environment when we did come across them. We did have a few hiccups when we launched the patch in terms of scaling issues, but a lot of those were addressed rather quickly and that’s due to the technology we’ve developed to hot-fix our servers and almost anything in the game without down-time.”
Excess Potion of Accelerated Learning: Acquired in your Garrison (part of the Warlords of Draenor expansion), this gives you a 20-percent bonus to experience from killing monsters and finishing quests. It lasts one hour, but you can buy it multiple times and use it back-to-back. Alliance players buy it from Sergeant Crowler, horde players buy it from Sergeant Grimjaw. Does not work above level 99.