I use the one on the Wave a lot (but never for adjusting my glasses ). I do have the little mini driver in all my SAKs with corkscrews but rarely use it. The ones on the Juice and Squirt get used occasionally, and the little phillips on the Ramber is excellent for kids toys.
At the risk of sounding imbecilic, I never knew the tiny screwdriver has a tiny phillips head on the other end until some 4 years after owning the wave.andWorse yet, it was by accident that I found it.
I carry an eyeglass repair kit (screwdriver and spare screws) in the glove box of each family vehicle. I haven't had to use them often enough to warrant carrying them on my person.
I know this is an old reply, but I haven't been here for a bit. What I have done in the past is forget the screw. It usually gets lost anyway. What I did was to take a paper clip, and bend a "U" about 1/4 of an inch long, the legs, and slightly tight together. Then insert the thing into the screw hole then slightly crimp the ends together. This fixes the lost screw problem almost permanently. Just my experience. YMMV...The Aerojet