None of us are invulnerable to the lost spring/small part gremlin. Even Superman has lost these small springs. Here is a tip I use with T jet, AFX type cars. I put a tiny amount of super glue in the corner of a pickup shoe spring. This keeps the spring in place so it does not get lost and helps when putting the shoe back on. Don't use to much or you will destroy the spring if you have to replace it.
Have had some good luck sweeping the area with a hand broom. Working on your cars inside a steel cookie sheet helps to contain many of your stray parts. Steel isn't necessary but comes in handy with magnets and magnet cars.
Another trick that works is to dim the lights and shine a flashlight across the floor surface. That kinda highlights anything sticking up. Often when I'm looking for one item, I will find parts dropped previously.
A long bar magnet attached to the bottom of an old sponge mop is often successful at finding dropped steel parts.
One time I dropped a pancake motor brush and couldn't find it anywhere. Two days later it showed up in the tread of a work boot.
I have used the "search light" method with a flashlight on the floor. doesn't always work. and yeah, I always find something else. many folks use a box of some sort to work in so dropped stuff cannot roll away. on MicroMark I saw an apron that attaches under the edge of your work area and around your neck to catch stuff rolling off, should be pretty easy to make your own. I get up and down from my chair too much to wear something tying me to my work area. first thing would happen is me getting up and upsetting the whole work bench!