Dust can indirectly hinder performance, as it builds up on the HS and fan blades it will keep the fan from moving as much air(can also shorten its life as mentioned) it can also hinder the HS from being able to dissipate heat effeciently. I recommend using compressed air to redmove dust. I would not recommend using a micro vacuum inside the case, as the motor creates an EMF which can potentially kill some components(this is not common, but is possible) If you want to use a vacuum, I'd recomment using a shop-vac with one of those mini-vac kits.