I use a paper notebook, turned completely backwards, I work from back to front - Put dates on every entry... Thus when it is full I can read it like a book, I also Post-it tab every important entry.. I prefer the 70pg .70 cent notebooks with a spiral bound, also picked up a $1 portfolio at wal-mart, my boss taught me this one; he has used it for 5-10 years with great success. He can look back to when we build this building (7 years ago) and tell you the exact paint on the walls and the carpet he used and dimensions or each room...

write the range of dates on the front of each notebook then stack them in order...