Choose the right memory card capacity.
Card sizing needs both halves of a shoot costed separately, because photos are priced per frame and video per minute. Adding a twenty-five percent margin is not padding: you will shoot more than planned, filesystem overhead consumes a slice, and running a card to absolute capacity risks a corrupted final file. Rounding up to the next real product size is the last step.
Space required
Required GB = photos x photo size MB / 1024 + video minutes x GB per minute
Card selection
Recommended card = smallest standard size at least 1.25 x required GB
For raw stills at 20 to 30 MB each, 64 GB holds roughly two to three thousand frames, which covers most single days. Video changes the answer entirely and usually dictates the size.
For stills, only for burst clearing. For video it is decisive — an insufficient sustained write speed causes dropped frames regardless of how much space remains.