it also depends on what current you have the driver set to. the higher the current, the more heat is generated. if your going to push it pretty high then yes, use a duty cycle of 1-2 minutes on to ~1min off.
EDIT: i forgot how much of a royal pain in the ass it was to get verified with paypal. worse comes to worse i might have to ship on mon or tues. i couldn't add my bank account since its already on my personal account so i had to start a new online checking account and having to verify the small deposits and such is beginning to be a royal pain in the ass. paypal wont let me print labels w/o adding a backup funding source which makes no sense b/c you guys money is in there now. i dont understand why i have to have a back up funds source when theres funds in the account!