Learned this trick from my dad half a century ago. Make a drawing of the whatever you are working on, if it is small, like saw parts you can trace it. use a small nail and poke a hole in the drawing or tracing where the screws and bolts go *as you take them out*. Insert the screw or bolt in the appropriate place. Putting it back together is much easier that way, you can't mistake what goes where.
You can stop a project half way done, go away for a year if that happens for some reason, and come back and you won't screw up (pun intended) putting it back together and no need to remember it exactly. It's only *slightly* slower than dropping them all loose in a can, but much better overall, especially if you are working on unfamiliar things or have two dozen projects going at the same time (like I always wind up doing).
