How can I tell ? I've bought him his own duvet.
I'm heroically committed to a program for keeping the dog off the majority of the household furniture. My strategy is thus; I have one (wipe clean!) sofa I don't actively discourage him from clambering on. The majority of the time, he sleeps on this overnight, even though to my eyes his basket seems as if it would more comfortable.
When the wintertime arrives, and the nights get colder, he's not so keen on an unadorned sofa. I can tell this because he starts to seek out nesting opportunities in more upholstered regions. The way that I combat this is to pile up a few cheap throws or blankets on the permitted sofa, which gives him something to nest in. Of course, the actual, correct, dog-basket is padded, upholstered, lined with welcoming cushions and blankets, and positioned in front of a good radiator, but somehow none of that seems to matter. It's all about perceived status with dogs, and so far as he's concerned, sofas are extremely swanky real estate.
To try and keep the winter sofa throws looking less manky after a couple of nights, I've tended to buy woollen ones. Light coloured rough wool doesn't show up the dog hairs so badly. In my heart, I think that I'll source them from local charity shops, but in practice they never seem to have anything suitable, so usually I end up buying them from shops, as cheaply as I can manage. Every once in a while, if they're looking particularly tired, I recycle the blankets in the rag box. The rough fibres are a too successful hair-trap; I wouldn't consider letting them near my washing-machine's expensive German filters, and I'm too lazy to clean them by hand. Then I buy some fresh ones, and restart the whole cycle.
Which leads into the current ridiculous state. IKEA is a particularly useful source of very cheap and fairly durable blankets, and it's only a few minutes walk down the road. This time I was wondering about experimenting with something a bit more sustainable, a fabric I could more easily clean, using our wonderful new VAX, with it's miracle pet-hair removal tool (which is actually the stripped floorboard tool I think, the 'pet' edition of the same cleaner was more money for the same suction).
I strode around a spookily empty IKEA (daytime, recession, Christmas panic shoppers busy elsewhere, wonderful!) trying to decide between a handful of different less-than-a-fiver options. I was suddenly flummoxed to encounter pile of somewhat rudimentary, lightweight double duvets selling for £2.78. A preposterous new plan quickly formed.
And so I bought a duvet for my dog. We put a cover on it from our store of past-it's-best bed-linen, and arranged it on the sofa. He seems very happy with it, but I can't help feeling some sort of key principle of domestic husbandry has been roundly subverted.