I find it a lot more work for the blade on a 48 hour shave than 24 hours, but at 48 hours the shave is usually closer.
My whiskers are very stiff at 24 hours. I remember testing that and they didnt become easier to cut until 44 hours or more.
It was a bit funny yesterday. I was watching closely as I shaved N>S under my nose. Even just shaving under one nostril at a time with a fresh Polsilver, I could watch my entire upper lip move from the resistance against the blade with my usual amount of skin stretching. Shaving the sides of my mouth N>S was the same. I could make one side of my mouth frown there was so much resistance. I was shaving slowly enough to exaggerate that though.
Things you do when you're bored! haha.