It depends a bit on which film you're using. Like others have said you have to develop to be sure, but my experience is that the "major brands" (Kodak, Ilford, Fuji) are quite resistant to light leakage if wound tightly. One brand seems to get edge fogging no matter - Bergger - their backing paper seems more porus, resistant to tight winding, and might even be shorter (though I have not done a comparison with a ruler to other brands).
I, too, wrap with aluminum foil - just to be safe.