Be aware that this can be completely different between HDDs ("spinning rust") and SSDs. HDDs don't get data cleared until it's explicitly overwritten, SSDs with OSes that support TRIM shouldn't have a lot of stray data left behind.

Also when wiping SSDs get something like Parted Magic (since at least 2018 likely earlier) that can properly erase SSDs. DBAN is NOT appropriate for SSDs in any way - extra wear from the writes, and wear leveling means you have zero idea where they're actually going.