It depends on the negative. Easy negatives require a single test strip and result in a good print right away, difficult ones may take several strips and full sheets. And sometimes I just can't get it right at all...
I scan all my negatives and try to work out the general idea of dodging and burning digitally on my phone. That usually gives me a decent plan for printing in the darkroom.
Difficult ones I work out on small paper (4x6 or 5x7) and only when I'm happy I'll make a larger print. My dr timer allows for working in F-stops and calculating enlargement factor based on current size and desired size and that works pretty accurate for me (as long as I use the same paper ofcourse).
One time in the darkroom, while teaching pinhole photography to high school students in Japan, I pulled the 4x5 paper negative out of the camera and said, "right!", and a kid flicked the light on. R's and L's have always been a bit of a challenge over there...I was setting up to print a negative today and forgot to switch out the white light lever before doing my first test - that was a "wasted" 4"x5" sheet
But generally, I agree.
And if you do a fair amount of toning, even the properly made test strips are useful, because you can use them to gage the amount of toning you do.
The 8"x10" print I made today - sort of a refined work print incorporating what I intend to include in an 11"x14" print - took 3.5 8"x10" sheets of paper. That was one wasted 4"x5" grossly over-exposed test strip (the white light one), one useful 4"x5" test strip, one 8"x10" print that was too dark - reflecting a mis-read of the test strip, one 8"x10" print with good density and contrast but needing a small amount of burning and dodging and one final 8"x10" print incorporating that burning and dodging.
It was of a forest scene exposed with a 6x9 pinhole camera, so it isn't an "easy" negative to print.




