[jacquesm]

> simply because we can't try before we buy.

In many countries this is not true and a 'right to return' within a certain period of time is proscribed by law unless the item is custom made for you or in auctions.

[microtonal]

That's a good point. But it is very short and often restricted to online/phone/doorstep purchases. E.g. in the EU it's fourteen days:

http://europa.eu/youreurope/citizens/shopping/shopping-abroa...

Which is short for a product which will take some time to evaluate (e.g. another phone/computer with a different OS).