So let me see if I've got this anywhere near right.
For the last few years I've always bought my shoes 'tight'. Think this started when I was buying climbing shoes. I reckon that to get a tight fit, I've also been erring on a too small fit
I'm just getting out of the habit because with my road and trail shoes I was getting blisters on toes and heel along with premature wearing of the heel cup on the shoe. My latest road shoes are the same model I had, but a 43.5 instead of a 42.....

Now for a fell shoe, I need to get them 'small' again? or is it just that fell shoes are by design a narrower fit than a road shoe?