Okay, let's try for a more concrete example. Salamence is switched in (from a death or into an EQ is irrelevant). You have out a Pokemon that can't do much to it (say, Gliscor taunting a wall and following up with EQ). What do you do? You could switch in a Sharder, a Steel-type, or a ScarfLatias or Scarfgon (not saying all of these are on your team, just that in building your team you chose one of them as a Salamence check). There are four main moves it could use (assuming the DD build, which according to the November statistics has a 50% prevalence): Earthquake, Dragon Dance, Outrage, Fire Blast. If they use Earthquake, they can OHKO your Sharder and Steel-type but not your Scarfs, if they DD they can bash up your Steels (and sometimes Scarfs), if they Outrage your Sharders and Scarfs are gone, if they Fire Blast they can kill the Steels and Sharders but barely scratch your Scarfs. You can suicide the Pokemon you have out, of course, but that puts things into revenge-killing territory, which has already been discussed. If both players have no information, it's really a crapshoot as to what will happen. However, if the Salamence player has already scouted out your check, then you can be in serious trouble, as they can then pick whatever move is difficult to impossible for you to counter. If they kill your check, then you're pretty fucked, unless you have two or more checks (which could be deemed excessive, although many checks serve multiple purposes). Even if your switch-in goes perfectly, and Levitate eats the incoming EQ, you can still be screwed because there's nothing stopping Salamence from just switching out. Salamence can come in later, after the threat has been neutralized, and sweep with ease. Finally, and this is the nastiest thing of all, all of this guesswork with switch-ins and predictions is based on only 50% of all Salamences. If the player has something not DD, then your cunning psychoanalysis of the opponent's character is thrown out the window. Pure strength isn't going to be what makes Salamence uber, unpredictability might. See Mew for more details.