I use the clear Printfile sleeves, I write the date and location also the negative nubers on ech sheet. Theses are themn stored in ring binders in my darkroom, in two large Really Useful Boxes. Reality is I now need to start a third box
My negs are numbered consecutively and stored in glassine sheets. These are then stored in stacking 4-ring drawers so they're kept flat.The drawer units are in the darkroom so i can file and retrieve quickly. I don't write on the negs.
The numbers and all the shooting details are added to an Excel spreadsheet which is backed up in several different places.
My negatives are in Printfile sleeves, stored in a 4 ring binder. Nothing is written on negatives or sleeves. All negatives are scanned, and a contact sheet equivalent of each page printed to be filed with the negatives. This contains the negative numbers, running consecutively up from 0001 with the binder number (and type) as a prefix. e.g. LF010023 would be the 23rd negative in large format binder 01.
These contact strips can be viewed on my computer to enable reasonably fast access to a negative. Except that when the number of sheets exceeded 100...