This is a good video on repairing and servicing a Bulova "Wrist Alarm" model.
I was surprised to see just how complicated this movement was and all the extra components that handle the alarm aspect.
I'm always amazed how the guy servicing the watch flips the balance wheel and assembly. Also he just lays all the parts in a mixed up pile. If I did that I'd very quickly lose track on what is what, especially the screws.
We were trained to use compartments in a tray with a lid. If you even mix up a single screw, it will likely become obvious later, but anything that wastes time is obviously counter productive. The more complex a movement is, the more critical it is to keep the screws organized. Chronographs have very specialized screws, for example. Sometimes screws will only go where they are supposed to go, but not always.
A lid on a tray also keeps dust off the parts and the tray prevents them from rolling around the work surface.
That said, the pile is in a kind of order, he likely lays these out the same way every time.
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