I'm trying to come up with some sort of comprehensive solution to the
various situations where I need either reading glasses or sunglasses.

I'm 44 and I use weak reading glasses. The problem I'm having is that
I often don't have my reading glasses with me. For example I'll go to
the grocery store wearing my shades but if I need to read a label I'm
stuck. I'm trying to figure out some sort of simple solution so that I
can read and have protection from the sun most of the time. I was
thinking about getting a pair of transitional bifocals where the top
half has no power and the bottom has my reading prescription. By
transitional I mean the kind of glasses that darken when you go in the
sun. These would work in most cases except for 2 situations, driving
and at work. From what I understand these won't work in the car
because they won't "darken". Also I prefer normal reading glasses at
work since I spend most of my time reading either a monitor or print
and I don't want to do that with bifocals.

So here is my plan. Have a pair of transitional bifocals that I wear
most of the time. When I get in my car I'll switch and put on my
normal sunglasses that I keep in the car. When I get to where I'm
going I'll switch back to the bifocals. When I go to work I'll switch
to normal reading glasses which I will keep at work. So my solution
requires 3 pairs of glasses.

Anyone know of a better plan?