According to Narutopedia for Shisui's MS ability Kotoamatsukami...
Itachi noted that the dōjutsu required at least a decade before it could be used again.
Does this limitation apply to Shisui, or does it just apply to those that took his eyes (Danzo and Itachi)? Because if this applied to him, then he's not as OP as everyone thinks he is. Plus how would he know it has a recharge period of 10 years?