How do I know if IVs on a pokemon is good or bad (like 2 IVs above 27 or what). How do I know if its worth keeping to train to 100 or keeping it with me to elite 4? And how do I know which IVs to looking for on a certain pokemon. For ex if I got an eevee, how do I know what IVs to look for on an Eevee(attack,sp attack,etc). And what is the deal between attack and sp.attack? Same with defense. Which one is better? What is the differences?
Same thing with EVs. How do I know which EVs stat I shoud max? Like Eevee attack/hp or attack/defense?
And how do you know where to train that EVs stats?
And if i catch I good IVs pokemon but the its nature is contrast with its good IVs stats, is it gonna worth anything?