In all the years I have been in the computer repair business I have cleaned more dust and gunk out of computers than what is necessary. I have yet to see it be the cause of a component failure except in 1 very special case. It will only affect your performance if it gets in the CPU fan/heatsink but then you will notice this right away as the computer will start running hot (assuming this is a laptop) it will collect dust in every small space inside of it, there is no way around it and it will not harm the computer just take some compressed air once a year and blow out the vent ports on the bottom and side of it and you will be OK