Secondary science teachers, do you keep master hard copies of your units, in a binder for example? Do you keep hard copies of answer keys? Do you keep both hard and electronic copies? Essentially, how do you organize your curriculum? I've tried keeping a binder for both master copies and answer keys, but it's been difficult to implement. My electronic file system is a bit unorganized, but generally arranged by unit. Suggestions for a filing structure or system would be so helpful. Looking for advice, tips, suggestions, etc. Thank you for sharing!