[REQUEST] Few questions on EVs

[Feax]

So i know EVs are statboosts that every pokemon can obtain simply by fighting wild pokemon.
Different Pokemon give different kinds of EVs.(like HP,DEF etc.)
There is a maximum of EVs a pokemon can obtain , max is 252. per stat.

I hope thats right so far , now my questions.

Do i waste EV when my Pokemon gets more than 252. EV in one stat or does it not count?

Can i reset EV points if i did something wrong?

Does the EV value stay the same when the Pokemon evolves or do i need to give it again EV training?

lookin forward to see your answers, thank you.

~Feax  :D