Hi Mark, one other thing that I should mention is that you often times may want to avoid actually modeling little tiny but heavily detailed pieces such as the screw threads on a bolt if you have a whole lot of them in your model.

The surfaces that make up threads like that will be pretty heavy with a lot of control points in them, so they take up a fair amount of memory size for each one. If you then have say hundreds of those (with them all actually not even visible), that will end up making for a very heavy model, affecting things like redraw time, memory consumption, and file size on disk.

If you don't have a whole lot of them, and you are using a few of them for a detailed zoom in view or cutaway illustration or something like that, then that kind of thing is fine.

- Michael