Wow gold players would have gotten the damage from the extra spell.
It is rarely a good idea to recast a DoT before it completely runs out due to the way DoT spells work. Let's take Corruption as example, it ticks every 3 seconds, meaning that 3 seconds after you cast, the DoT ticks dealing its first damage. It will totally tick 6 times if not cast again.If you had cast something else and left it alone, wow gold players would have gotten the damage from the extra spell. Additionally, you lose 1 second Global cool-down casting something you didn't really need to cast yet. Even worse, if you recast Corruption one second after the 5th tick, you will cause there to be 5 seconds between ticks, you will miss casting something else, and initiate the Global cool-down before your next cast. You get the idea. It's better to have the DoT fall off while your getting in an extra Shadow Bolt than to clip the DoT by recasting before it runs out.To some extent, channeled spells like Drain Life and Drain Soul work similar to a DoT, only unlike a DoT you have to interrupt the channeled spell to cast anything else, losing its damage until you begin to channel again. However, Drain Life and Drain Soul still tick while being cast, causing damage every 1 or 3 seconds respectively before considering Haste.Warlocks are a bit different classes than others in World of Warcraft. They have pets and have to focus on Stamina as well as Intellect, just unlike the Mage.