I tend to use notebooks filling all the space, its a professional habit, as with Tim M my lab book must be written on every page, and my copper notebook must be space filling to prevent accusations of later alterations if it becomes evidence in court.
I usually start a new day's entry on a fresh page, but slash out any unused white space on a previous page. Every page is signed and dated, with important findings countersigned by my boss. Yes, things can get this anal in science.
Sounds familiar. My lab is incredibly anal because we're analytical - everything must be traceable, all possible sources of contamination logged and dated, etc etc. In my other life, a police officers' "original notes" hold evidential value, wherever they are written. I must preserve the original copy, or it's 'destroying evidence'. So if I write a car reg on the back of my hand, I must photocopy my hand, sign it, date it, and have it countersigned and dated by a ranking officer.
