For me, there is a disconcerting difference in size between things as seen through glasses or contacts. It may sound ridiculous, but I think it may have partially contributed to some of my weight gain this winter. I stopped wearing my contact lenses immediately after our wedding at the beginning of January. Everything appears MUCH smaller with my glasses on, so I think I was able to ignore some of the visual cues. I went without wearing my contacts until the end of May when my husband and I climbed a small mountain in the Adirondacks on a rainy, humid day. My glasses became a liability, and I realized I wouldn't want to deal with that while climbing High Peaks this summer.
But after wearing my contacts again for only two months, I'm desperately tired of them. I don't like not being able to see well and the dryness is beyond irksome. On our recent hike up Seymour Mountain my poor sister was forced to carry her glasses more than she was able to wear them because of the humidity. My eyesight is so bad I can't imagine being able to take more than two steps without smashing into a tree or tripping over a rock (two things I do regularly even with corrective lenses).
My guess is as soon as the snow flies in the mountains my contacts will take a long winters nap. I'll just need to remember not to be fooled by the illusion of smallness created by my glasses.