It's always good to have a spare/back up, especially for work.
As a teenager and in my 20s riding dirt bikes, since I visited deep remote deserts a lot, all of my daily driven VW station wagons (Squarebacks) and dune buggies had 2 coils mounted side-by-side and I carried another complete 009/050 distributor wrapped with plastic cling wrap. I always carried 2 full size spares to the desert. If any issues with the coil, simply plug into the next one. And one trip, we even needed to use the second spare tire.
When I drove up and down the state for L&C survey work, I carried a full size spare in addition to the compact spare and always carried 2 sub-zero mummy sleeping bags along with a week's worth of food and water ... And a Glock as during the 12-14 hour drives, if I got tired/sleepy, I would pull over and find a spot to sleep/camp for the night. (Ah, happy memories)
I bought a spare Glock 22 when I switched USPSA caliber from 45ACP/9mm to 40S&W. Any issue during the match (Yeah, I was lazy and shot thousands of rounds before I cleaned my Glocks shooting matches), I simply grabbed the other pistol.