When start a new design using a part you have dozens of copies Spice models for, which one do you choose? Or do you download yet another copy?
It depends, but I sense the questions are rhetorical, so won't go into details. I have a local repository from where I usually checkout the models into new projects. I prefer to keep a local model copy with the project. Also it happens sometimes to modify existing models, or to build my own models, and so on.
Each uses own way of organizing files. To me, the most important is for project to be self-contained, and to be able to open them later.
I prefer the models to stay together with the project, because I have projects that sometimes span over many years.
For example, some SPICE project I have are in PSpice, from when LTspice was not yet a thing. I might still have a few SPICE projects that are even older, from the era of PDP-11, when there was no GUI, no IBM-PC, no Windows and no Internet. The schematic was typed as a network of nodes, and the simulation results were plotted with 'x' and 'o' letters on tractor-feed continuous paper, on a printer that was hammering the letter like a typewriter, fun times.
