Item restrictions were unheard of when Competitive DotA was fresh. Many of the items were used and abused to get to the top rankings of tournaments. The first item that was abused to its maximum was the Necronomicon, which allowed teams to put pressure on the opponent easily. Later on we saw the mass mekansm strategy, allowing teams to mass heal damage from enemies. After some time, this was seen in the eyes of players as abusable and was either nerfed by IceFrog, or removed from tournament player.

Common Item Limits
Two Mekansm
Two Necronomicon
One Refresher Orb
One Arcane Ring
Two Euls/Guinsoo or One of each.

Item Prices
Necronomicon Level 3: $5350
Refresher Orb: $5575
Mekansm: $2434
Arcane Ring: $1700
Eul: $2800
Guinsoo: $5175
Blink Dagger: $2150

Are these item limits actually needed?

In the early stages of competitive DotA, two to three Mekansm's were seen by each team in almost every game. This was seen before the item got nerfed, when the AOE heals would stack. Now, mekansm is only found on heroes such as Pugna and Twin Headed Dragon. When asking Jonas 'Fragalot' Tesfay of Back to Basics about the Mekansm limit, he stated, "No, it shouldn't be there, it doesn't work like it did before when you could do 5 meks. You can't do them at the same time, you have 2 wait between them, and so it isn’t really effective to stack them since your whole team can’t use all of them."

Mike 'Dead' Giardullo of Exponential added, "I'm not really PRO for the ban being removed, but any team that goes more than 2 Mekansm's will be at a disadvantage stats wise, since they don't stack, and their heroes will be really weak."

As said, Necronomicons were very much abused in the early times as well. At one point we would see teams using upto 5 necro books, which had a 500 mana burn at level 3. This allowed teams to push their way through the enemies base with ease. In the map version 6.28, the book only burned 250 mana at level three, and gave 100 gold. Later in version 6.42 the mana burn was lowered once again.

Vanya 'Vigoss' Shink of Virtus.Pro shared, "2 books, mass books are imbalanced. The reason is because it is such a cheap item to buy and has good usages like mana burn and vision and speed burst. When there was no ban on books, everyone just bought books, and ruined the purpose of the game. Mass books = push strats like crazy." Shink did state a possible fix for the 'mass necro' strategy. He claimed it could in fact lead to books being unbanned from league play, "I think books we be allowed if the blue one didn't do 600 dmg."

Teams such as Pandemic tried to counter this strategy by getting 2-3 diffusal blades, however this did not always work. One could also take a stance by saying massing books could increase the speed of the game, which could make the game itself more spectator friendly.

How about the limit on Refresher? Have you seen a Refresher recently on any hero? Maybe warlock? Normally teams will not even get one Refresher, or even think of getting two! Josh 'p0sitive' Yu of Pandemic stated, "I don't think it should be limited anymore, I'm pretty sure the item restriction was installed because DotA before was huge 5v5 battles, and that would determine the game. Not to mention AoE high cooldown skills." Why limit an item that isn't even used?

The Arcane ring was limited because it gives mana in a small AoE around the hero, key for harass strategies and fast pushes. Arcane was looked at as the mana version of the mekansm when it first came out, which is why the limit was put into place. 135 mana at an AoE considered abusable? While examining the specs, $1700 for 130 mana, 3400 for 260 mana and so on, one can wonder how that is seen as abusable.

Steven 'Splash' Hua of Virtual Sports agrees, "I think it's pretty useless to have 2, because thats like 1.7k away from you and if half the time you are probably going have full mana or close to full mana if someone else has arcane."

Now getting into the major abuse areas, the Eul and/or Guinsoo spam. Earlier in the Competitive DotA scene, you would generally see about three heroes getting Eul or Guinsoo, this would allow you to cyclone 2-3 heroes, while focusing the others. The only ways to counter this strategy was either- Use Silencer for Global Silence, Mass BKB’s, or get Euls/Guinsoos of your own.

The cyclone abuse was limited by decreasing the duration of the spell, and adding a cooldown. This cyclone strategy was used in perfection in the CPL winter finals match between Check-Six and eMazing Gaming. eMg kept Check-Six's heavily farmed visage in the air long enough to take down heroes, towers and also raxes.

Sean 'Cubs' Winkler of goingLive stated, "Yes, it should stay as two. In particular, I remember one DXDI game on east in which the opposing team bought 4 euls. They were able to cyclone all of us and destroyed our raxes. We were not able to do anything, not even protest it because DXD never specified in their rules about a eul/guinsoo limit. That item needs to be limited because it is too abusable." Increasing the Cyclone cool down could do the trick with this abuse!

The evolution of Blink Daggers in Competitive play has created quite a bit of controversy. On one side, multiple blink daggers make for a lot more action during the course of the game. As a result, viewers think that the game is much more fun to watch compared to the old mass farming days, however the players themselves are unable to create new strategies. It makes it more difficult because they must focus on countering the mass blink dagger strategy.

Doug 'Wedge' Anderson of Pandemic stated, "Having too many blink daggers inherently changes the way the game is played, which restricts lineup variation and strategies. Basically every hero on your team needs to have a stun, or needs to get a sheepstick to be effective."