I can see that it would be much more common to send back clothes than gadgets.
With gadgets (tools, technology, etc) the demos USED TO BE very good and you could judge whether they would be useful for you. So I've never had to send any back, and I've been grateful to Q for showing them to me (even if I've bought them elsewhere).
What happens with technology is that better things come along, and the old ones are discarded.
For example, the iPad is notorious for not having any connection sockets to put photos, music etc on an off it.
So Q showed me a gadget that connected to it via its own wi-fi (not your home wi-fi, so you could use it anywhere).
This was very useful, but a bit long winded. Then Q showed me a special memory stick with a USB one end and an iPad connector on the other. This was much easier, so the other £100 gadget got relegated in favour of the new £100 gadget.
And this sort of thing has happened time and time again, in particular with cameras. Over the 12 years I've bought 3, as each one was so much better, even though about £300 each (all TSV's). But I don't intend to buy another one as the one I've now got does everything I want (eg a huge zoom). I don't need gimmicks like face recognition, or only taking a pic when everyone is smiling, or tags each photo with your location.