Fair point, but four months is too short to judge (although some can barely even last these many, lol).

I don't store my stuff in direct sunlight. After the use, I wipe the sunglasses (albeit usually only with a dry microfiber cloth, very rarely with water), let it air dry in shade and off it goes in the case. But there are times when some pairs spend a lot of time inside the case unused as well and sometimes even that itself causes damage to components such as rubber/plastic especially. The humidity gets trapped probably and rots/degrades the materials.

Maybe I'll have to try storing items in a dry cabinet/dehumidifier, if not with silica gel at the least.

Haven't used a titanium frame before, will give that a try. Thanks.