I don't have a bathrobe and, since I rarely wear clothes unless I have to go anywhere, I also don't shower or bathe except on those rare times. I'd prefer not to get clean clothes dirty. And, the reason I don't shower or bathe is because I don't sleep well. And, there are several reasons why I don't sleep well. It's not as simple as having insomnia. Sure, that could be a factor, but it's not the primary reason I don't sleep well. I have both physical and mental problems going on with me. It's a long story and I can't really explain it. You just have to take my word for it.
As for getting cold in the Winter, Winters around here have been seemingly milder than they used to be and, sure, sometimes I need to turn the heat up on some cold nights, but I use the heat far less than you might think. So far, I've only used it once or twice this season and it hasn't been too high. 72°F to 74°F is usually all that's needed for me to stay warm. Plus, I can snuggle up under blankets if I still need some extra warmth. I'm a cold-weather person, so it usually has to be very cold before I feel the need for a lot of warmth. In contrast, I sweat far too easily, even if it's not very hot. Is it any wonder I prefer not to wear clothes?