Easily the number one reason our repair center sees for blown motors is after picking up very fine plaster/cement dust. This type of dust is particularly messy and gets through filters. If it gets through the motor filter, particles can settle on the motor bearings and act as an abrasive to wear it down. Sometimes we see this dust clogging up the electrics of the motor causing short circuits. If you use your vacuum cleaner for this purpose, be aware of the above and show extra care at this time to maintain your machine. If you engage a builder or tradesman, ensure that you make a point of telling them upfront that your vacuum cleaner is not to be used and that they should bring their own to clean up when they have finished their work.