Unless you often find yourself in the dark wishing for that extra stop, why worry? In general use one would be endeavouring to get the best out of any lens by using as small an aperture as possible anyway, and once one is up above f4 or so there's much less difference between lenses in any case. I have the f1.8 50mm standard and can't remember the last time I used it wider than f4. But that's just me - I tend to try and keep the aperture as narrow as possible even if the shutter speeds drop right down.
Jim.