It seems as if many of you have a lot of time on your hands (maybe too much...) when in the darkroom. Who really needs to worry about avoiding particular exposure times, or spend time multiplying and dividing by fractions of an f-stop?
For me it's whole stops on the lens, exposure times that allow me adequate accuracy (how the heck do you expect fractions of a second to be accurate with any timer?), and time for dodging. I prefer times in the 20-40 second range.
And, I alter exposure by percentages (and I make my test strips in percentages as well, rounded to the nearest full second), not fractions of f-stops, which seem overly unwieldy in the darkroom to me.
That and a metronome and I'm in business. I like simple and low-tech.