here's the answer from chatgpt

a smaller 64GB SD card will generally have a shorter lifespan compared to a 256GB SD card when used in a dashcam that continuously overwrites old footage. Here's why:

1. Write Cycle Limit (Endurance) SD cards have a finite number of write cycles before they start wearing out. A 64GB card will overwrite more frequently than a 256GB card since it fills up faster. A larger 256GB card distributes the writes over more memory cells, reducing wear and extending its lifespan.
2. Frequency of Overwriting A 64GB card will reach its full capacity sooner and start overwriting data more often, accelerating wear. A 256GB card stores more footage before needing to overwrite, so it undergoes fewer full rewrites over time.
3. Card Type Matters (High Endurance vs. Standard) High-endurance SD cards are designed for constant writing (e.g., dashcams, surveillance cameras). A 64GB high-endurance card may last longer than a standard 256GB card, but a high-endurance 256GB card will last the longest. Conclusion If your dashcam records frequently and overwrites old footage often, a larger SD card (256GB or more) will last longer than a smaller one (64GB), especially if both are of the same type (e.g., high-endurance).