Back in the olden days when all we had were manual typewriters (I didn't type on an electric machine until I was in the service in '72) all manuscripts were double-spaced to leave room for redaction. Now I think they are double spaced to accommodate the aging eyes of most redactors. If an idea pops into my head when I am away from home I will jot said idea down 0n anything - a cocktail napkin (one of my favorites), a notebook (I keep one in the jockey box of my truck for use while being stuck in traffic during the interminable road constructions so common to the Rocky Mountain West during the summer months), a piece of cardboard - anything I can write on. When I get home I stick the great idea note somewhere where I will be sure that it will never be found. Sigh...