I also think about how easy it is to track a parcel once it ships. Nose pads that are too hard leave marks and feel uncomfortable on the skin. Clear product descriptions save time and reduce the chance of disappointment. In the end it is all about finding what matches your own habits and lifestyle.

If anyone is interested in real user experiences, I sometimes write short notes about the shops I test.
You can find one of the pages here:

visit this page

Sometimes one good quality item is better than five very cheap ones. Forums, blogs and communities create a kind of collective memory for shoppers. Sometimes I still make mistakes with size, so a friendly exchange policy is very helpful. Online shopping will always have a bit of risk, but experience makes it easier.

Maybe this is useful for someone.