I intentionally worded the title like that to avoid spoilers, so here goes the spoiler:
The Master Sword needs to recharge its energy when you use it too much. How exactly does that work? At some point you get a message, similar to weapon durability, “Your Master Sword is running low on energy” and finally after more usage that it ran out. How long does it take to fully charge? Can I speed up the process? It seems like I can almost never use it, because the recharge takes so long.
It takes 10 real time minutes for the Master Sword to recharge after “running out of charge”. This cannot be sped up.
Bigger spoilers ahead:
Note that when fighting Guardians, Divine Beast bosses, and Ganon, the blade will glow Blue and the damage will double to 60. While in this state, it has greatly increased durability and can be used for a great amount of time, as long as it hitting the above enemies. Hitting rocks etc while the blade is glowing blue will still lose durability at a normal rate.
Source : Link , Question Author : Ian , Answer Author : SGR