I've always had rounded shoulders and a hunchy back. I remember in my teens and twenties my mother constantly saying 'Stand up straight' or 'Head up, chest out', even though to be honest she also had a habit of hunching her shoulders.
Now at 78 I see myself in a shop window and think 'Oh lord, I'm all hunched over again'. I look so much better when my shoulders are back, but I can't remember to keep them there.
Many years ago, a physio stuck a giant X of sticky tape on my back to try to keep my shoulders back, but all that did was stick to my clothes.
Is there any way of forcing myself to remember to keep my shoulders back?
I don't think there is. It's the habit of a lifetime.