Why the card in your phone is the wrong card
A dash cam or security camera records in a loop, overwriting the oldest footage continuously, every day. A standard card designed for photos is built for occasional writes and fails under that load, usually silently, so the first you know is when you need footage and there is none.
A recording camera writes to its card continuously and overwrites the oldest file when it fills, which is a far harder job than storing photos. A card with a proper video speed rating, Class 10 and V30, is built to sustain that write rate without dropping frames. A cheap unbranded card will appear to work and then quietly start losing files, usually discovered on the day the footage mattered. Match the capacity to how long you want before the loop overwrites, and check the largest size your camera supports before buying the biggest card on the page.
Related
These are the cameras that need one: dash cameras, trail cameras, 4G security cameras and bodycams. All four overwrite the card continuously, which is what wears an ordinary card out.
Common questions
What size do I need? For a dash cam, 64GB gives roughly a day of loop recording at 1080p, less at 4K. Security cameras vary with how often motion triggers them.
How often should I replace it? Every year or two under constant recording, or as soon as the camera reports card errors.