In light of seeing some HD issues I thought I would arm myself with some knowledge if I ever have such an issue. I have a Mid 2010 i7 with a 1TB HD. If it were to ever fail, could I just run to a local store and pick up another HD and replace it without any issues? My main worries are with the fan speed issues people see with SSD's. Do most HD's have the thermal sensor built in? My iMac is my source of income so if it happens I want to be able to remedy it quickly.