I used to use f-stop printing - I calculated the times once and wrote them down on a piece of paper - starting at 1 sec and going up further than I'd ever need to use in practice. Then I just read the times off the paper.
I don't worry about forgetting to set the timer because I use use the method described in Ansel Adam's book "The Print". I have a metronome timer set to its max time. I control exposure with a black card and by counting metronome ticks. My sequence is:
1) Put the card under the enlarger lens and turn on the timer.
2) Count off 10 ticks (10 sec) to allow the enlarger light time to come up to full power.
3) remove the card and count ticks of the metronome to expose.
4) put the card back under the lens to stop exposure, then turn off the timer/light.

This should give you more consistent exposures as the enlarger light doesn't turn on and off instantly - there is a short period of time while the light warms up/cools down where the light output is variable.

I stopped using F-stop printing because I found it wasn't really worth the effort. It didn't really save me much paper, because after a while of printing, you get to the point where you can look at the negative and get a pretty good estimate of what the exposure should be. Given that, I generally don't need more that one ( or 2 for splitgrade ) test strips. What really uses up the paper for me is coming up with all the dodges and burns necessary to turn your work print into a final fine art print.

Color printing is another whole ball of wax. There I go through a lot of paper trying to get the color balance right. One way I've found to reduce the amount of paper consumption is to use small pieces of paper in important areas to get correct color balance/ exposure. For example, if I have a photo with a person in it, I'll tear an 8x10 sheet of paper into 4 4x5 sheets, put the 4x5 sheet where the person't face is, and use that to get the color balance right - this gets me 4 adjustments per 8x10 sheet instead of 1.