Have you tried using contact lenses to make one eye long focus and one eye short focus ("monovision" in intraopticlens terms)? Then you'd only need at most one middle-distance pair of glasses on hand.
Wouldn't you get a headache or have depth perception issues? Whenever I lose a contact in the middle of the day and don't have a spare it's very uncomfortable to keep the other in.
"Monovision" in the in-eye lenses is a very common choice for elderly patients having cataract surgery. There may be a period of adjustment, which you wouldn't have had.
I am not GP, but I don't have a problem with a single contact. What I find really neat is after hours of just one, the vision in my other eye is improved for a while; I can actually see decently from the non-contact eye when I remove the contact.