I've got a H/C plate, and if I'm driving myself around, I get out and immediately look for a cart so I can grab it to catch my balance and then I can walk in the store without worry of falling.
On some good days, I am able to walk with a spring in my step...although I'm always at risk of my leg giving out. On these days I do not park in the handicap spot, because I agree that the elderly should have a spot long before I should get one.
My pastor use to always tell the church, don't park in the handicap parking spot if you are not handicap...because it's like asking for an ailment....so on the days that I feel good, I want to park as far away from the h/c spots as I can.