Lets say you have an OLD SodaStream fizzer that your wife rescued from Goodwill maybe 15 years ago.
Lets say that beast of a machine has worked reliably, even after you modified it for a #5 CO2 tank because those little ones are expensive.
Lets say, one day, it made a LOUD hissing noise and didn't fizz anymore.
So you took it apart and discovered one of the (cheap) plastic fittings that held the CO2 feeder line in place sheared off.
So you replace it with a model you find on Thingiverse.
THEN .. while you are putting the OTHER end of the CO2 line back in place, you SUDDENLY decide that you are an orangutan, and using your trusty 7/16th crescent wrench, you CRANK THAT MOTHER LIKE A MODEL T FORD!
Subsequently when it shears, you are like ‘NBD man, I printed out several of that model, just in case.’
Then you discover there isn't enough clearance to fit one where the back end of the line attaches.
And that ‘thinner’ models don't exist, because you are apparently the only clutz who has broken that side of the line.

Well .. you might spend 5 minutes in Tinkercad, modifying the model so it will fit with less clearance, but still be a hex-nut .. so you can (gently this time) use a crescent wrench to tighten it down.

Here ya go. Printed successfully with 100% infill for strength.