Originally Posted by
Kralljin
In Legion, ES dealt damage based on Maelstrom, in BfA, ES deals full damage at 60 Maelstrom.
Previously (Meaning between 8.0 and now), people did save their ES until some Int / Vers / Crit proc, then used ES so it would be buffed or save it if they know they'll have to move before hitting cap.
Generally speaking, it isn't worth to delay ES as having it buffed by MotE is better, you cannot be sure that once you're at ~80-90MS that your next will be Lvb, unless you always save a charge.
You can do it, but in my opinion it's not worth the hassle, just make sure ES is buffed by MotE and you're set.