Many moons ago when I started developing black and white, I was advised to use separate fix for film and paper. I've followed this rule pretty much blindly ever since even though I use the same fixer at the same dilution for both, simply because I can't remember the reason given. Does anyone know if this is really necessary, just good practice or an old wives tale?

I've decided to start using a stop bath, I've used water up till now without any problems, but it strikes me as a good thing to do. Is there any need to keep seperate stop for film and paper, as I have been with fixer?