Each time you start a new machine sewing project or after 8 hours of sewing always start with a new machine needle. This way you reduce the chances of the needle becoming blunt and pulling the threads of your fabric. This is especially obvious when sewing lightweight fabric such as chiffon or silk.
To view sewing machine needles click on the following link http://koalaquiltnsew.com.au/shop/schmetz-sewing-machine-needles-universal/