In reply to mcdweeb:
I've kept a pair of Oakley goggles in my winter pack for the past 13 years; replaced them last week because the foam had died and they didn't sit comfortably on my face any longer.
They were oakley's cheapest ones but I think all their range feature flexible and impact resistant lens materials and very flexible rubbery frames. I don't use a case, just the soft bag they came with. They've never shown any sign of breaking. Fwiw, I'm usually out a lot in winter, so my sack gets a fair bit of abuse over several months.
I wouldn't waste money, space, nor weight on a case.
Post edited at 13:13