I'd like to discuss Stealth Rock and its effects on the metagame and the Pokemon in it. Stealth Rock is often seen as a move that is used exclusively in singles, and not at all in Doubles. This is certainly not true. While the move definitely does see more use in singles and is undoubtedly more useful with just one Pokemon on the field a time, that does not mean it is a completely useless move in doubles. Many people believe that there is next to no switching in Doubles, and that Pokemon simply stay on the field until they faint the majority of the time. This isn't the case at all, unless you are playing on the low ladder. In higher level play, there are many switches in a single game, often multiple happening in one turn. Many Intimidate users in particular get switched in and out regularly to repeatedly lower the opponent's Attack. This lets the whole of your team take hits better and generally gives you a better chance of winning. The same applies to Pokemon which you really need to keep alive if your opponent has a particular weakness to that Pokemon. Switching these Pokemon out lets them survive and potentially come back in at a later stage to deal a massive blow to your opponent. All this switching makes the threat of Stealth Rock much more real. However, there are significantly less turns in the average Doubles match than in singles, so Stealth Rock isn't anywhere near as good. Stall teams are also a lot less viable, to the extent of being completely unviable, so Stealth Rock isn't so useful for wearing these teams down. Stealth Rock isn't as good in Doubles as in singles, but it is still a good move, and worth considering, even if it's not for every team.
One of the biggest reasons to use Stealth Rock is the fact that many of the tiers biggest threats are weak to it, such as Charizard (especially Mega Y), Talonflame, Volcarona, Thundurus, Togekiss and Shaymin-Sky. Having Stealth Rock up makes these Pokemon a lot less willing to switch in and out as they please, and so limits them and what they are capable of throughout the match. All these Pokemon and more are greatly crippled by Stealth Rock, as it takes up to 50% of their health simply upon switching in, opening them up to being revenge killed far more easily by something like a fast strong attacker such as Deoxys-A, or a strong priority move such as Azumarill's Aqua Jet. Talonflame in particular already kills itself very quickly thanks to the massive recoil from the two moves it spams primarily - Brave Bird and Flare Blitz. With Stealth Rock in play, Talonflame's health drops remarkably fast and severely reduces its longevity.
Many Pokemon have access to Stealth Rock, but very few are both viable and able to give up a moveslot for it. The primary reason that these Pokemon can't afford to use Stealth Rock while they can in singles is the fact that many moves are viable in Doubles that see no use whatsoever in singles. In particular, Protect is used on almost every Pokemon that doesn't run a choice item or Assault Vest as it is a brilliant move that has many uses in Doubles, and it often takes the slot that could be used for Stealth Rock. Protect is also a good thing for Stealth Rock, however. If you predict an opponent to use Protect and you simply can't hurt the other Pokemon, or the opponent uses Protect with both Pokemon, then you are given a good opportunity to set up Stealth Rock, as it is not blocked by Protect. Landorus-Therian is a good user of Stealth Rock. It only really needs Earthquake, Protect and Rock Slide/Stone Edge - the last slot is pretty much up to preference or what your team appreciates the most. Stealth Rock is a perfectly viable choice for this last move, for the reasons I have already listed. Lando-T is also often bulky enough to take whatever hit it wants, especially with the assistance of Intimidate. Terrakion is also a good candidate for using Stealth Rock. It generally runs Close Combat, Rock slide and Protect, with something like Substitute, Earthquake or Quick Attack (feel like I'm missing something here but w/e) as a filler move. Stealth Rock is a good choice for this last slot if your team appreciates the support. Terrakion outspeeds many popular Pokemon, so can get up Stealth Rock reliably and without fail. Also, many Pokemon choose to Protect against Terrakion, such as Heatran fearing the Close Combat, which creates good opportunities to set up Stealth Rock. Other Pokemon that can fit Stealth Rock onto their sets depending on the team are Tyranitar and Garchomp. Heatran can also run it if you don't like Substitute, as many users don't (*cough*kom*cough*).
Pokemon that appreciate the support and residual damage that Stealth Rock provides include Choice Scarf Pokemon looking to revenge kill opponents, such as Gardevoir, Landorus-Therian, Genesect, and Kyurem-Black. These Pokemon like to have opponents worn down, even just slightly, as they often don't have as much power as other Pokemon thanks to their item being used to boost their Speed, and not their offensive power. Also, Pokemon that use powerful spread moves as their primary way to attack like the hazards, as their attacks don't do as much damage as single target moves because of the 0.75x power decrease on spread moves. Such Pokemon include Mega Charizard Y, Heatran, and strong Ground-types such as Excadrill, Garchomp, and Mamowsine. Landorus-Therian and Gardevoir also both fit into this category, so it is clear that hazards are very useful for both these Pokemon.
Some Pokemon are worse in Doubles than singles simply because of the general lack of hazards. Magic Guard Pokemon, such as Alakazam and Clefable, are immune to hazards as they switch in as well as indirect damage in general which includes weather and status, which makes them great for offense and stall respectively, because of their vastly different stat distributions. In Doubles, however, the presence of hazards is significantly less, so the usefulness of Magic Guard, and therefore the usefulness of the Pokemon themselves drops dramatically. Pokemon with Magic Bounce are also made worse because of the lack of hazards, so Pokemon like Espeon and Xatu are relegated to the ranks of bad Pokemon. Magic Bounce is extremely useful for keeping hazards away in singles, but not so much in doubles. There is also generally less non attacking moves such as Toxic, so Magic Bounce Pokemon just don't thrive in Doubles.
As you can see, Stealth Rock and other hazards have a significant effect on some Pokemons viability, and the popularity of Pokemon such as Charizard and Talonflame has a significant effect on Stealth Rock's viability. What are your experiences with Stealth Rock, and have you ever tried using either Spikes or Toxic Spikes? What were the results?
