TV is cheap. While a two hour sci-fi movie may get tens of millions of dollars and months of pre-production time to build an immersive world of futuristic technology, a TV sci-fi has to do the same thing on a shoestring. And it has to do it for 45 minutes every week.
Of course props are thrown together from whatever can be found at a hardware store with bits of Airfix models glued on. Not everything can be custom designed and built from scratch.
The best corner cutting method of all, though, is just to use whatever you've got lying around already. That space age medical scanner from a few episodes ago? We don't need that any more? Great, now it's a laser gun for this week's story.
And, while we're in the reduce, reuse, recycle spirit, what about all those other shows with props that they're no longer using? They're probably just gathering dust in a warehouse somewhere. They'd just be going to waste if you didn't give them another TV airing.
Yes, whether it's digging up something second hand from a warehouse, constantly picking on the same stock prop design, or giving a long second life to what was once an inanimate big screen star, TV loves a spot of prop recycling. Here are ten of the best examples.