What I have started doing is keeping digital copies, instead of printing.
I have created a folder on my computer called, "Elementary Education". In that folder I have LOTS of sub folders for different subjects and different sub subjects. For instance, my Math folder has sub-folders for Mutliplication, Division, Money, Patterns, etc.
I keep great ideas I find for all grades, because who knows what grade I will teach.
I am signed up for all types of teacher newletters. I get at least 4-5 emails a day. "Great FREE Math Sheets", "Fun FREE Printables", "FREE Lesson Plans for Earth Day!" I go through them quickly and glean the best ideas for my digital file. When I have my own classroom I will be more prepared!
In some upcoming posts I will share websites that have great resources.