How Crucial are Mega Evolutions to Competitive Success?

[adolf hipstar]

personally i think it is necessary for every team to have a mega pokemon.i have two on my team sometimes cuz if the first mega is KO'd without mega evolving then you got a revenge killer.i have teams with no mega pokemon and they work amazingly sometimes even better.but megas are for people who need that extra power if you think you can make a team without a mega then you have to be an expert battler else you're gonna be crushed by the opposing team.
-adolf hipstar