Don't buy the wife a power tool
I haven't got Roslyn a Christmas present yet. The plan is that she'll take me to the shops to teach me how to buy her jewellery. So I don't buy her jewellery that she'll never wear for one reason or another.
I'm awful at buying Roslyn presents. I think like a bloke. I've learned to watch for clues, the "Ooh, that looks nice" comments when walking through a shopping centre, that kind of thing.
But a few years ago (when we were still in London), I made a mistake. In about October, she had commented about a RotoZip when watching the TV. She said how useful it would be, and talked about some of the stuff she could do with it. So I made a mental note. Went to all kinds of trouble to find a hardware store that had one (very popular, sold out quickly), and eventually found a B&Q that stocked them. She saw the box wrapped up under the tree, and had no idea what it was.
I learned that year - don't buy the wife a power tool. Even if she really wants one.