My Mum used to say the same thing about removing a coat as soon as you came indoors to feel the benefit of it when you went out again.
We are so far south that it's still warm enough to wear t-shirts, silky tops and summer weight trousers. I only put a cardigan on if it's windy. On a sunny day like today the house is warmed by the sun and stays warm till bedtime. We don't usually light the boiler or use the central heating till early November. I wonder if this year will be different. Our children who live 100-150 miles further north have already turned their heating on.
I reviewed my winter wardrobe yesterday and realised I only have 3 cardigans and 2 fine knit jumpers. No winter trousers or fleecy pyjamas, I've never needed them. I tend to wear summer clothes right through the winter, including sandals. Haven't worn a vest since I was a child.
I do however have dozens of pairs of socks as my feet freeze at night (poor circulation), and 3 very warm coats should I need them. I may treat myself to some bedsocks this winter if they still make them. We have an electric underblanket (not put it on yet) but it doesn't warm my feet up sufficiently.
For those who are already feeling the chill I'd say put something warm on, layers maybe, why suffer the cold if you don't need to. Be cosy and comfortable.