As long as a nail is still straight, it can be reused. However you will often find that the process of removing a nail will bend or damage it, therefore to be able to reuse a pulled nail you would need to straighten it.This can usually be done by hitting the nail with a hammer against a hard surface like an anvil, until it has straightened out, but this can be time-consuming.
Most nail pullers are likely to bend nails when pulling them out, as the priority of nail pullers is usually to try to limit the damage to the timber rather than the nail.
Nail pullers do not put priority on saving nails because they are mass-produced and usually inexpensive, whereas timber often is expensive.
Because of this, many people choose to not reuse nails once they have been pulled and will just replace them with new nails.
Wonkee’s interesting fact:
Originally, nail removers were designed to remove the nails whilst preserving them to be used again, this was because up until the 19th century, nails were handmade.
Each nail had to be made individually so the process was time-consuming and nails were expensive and sometimes difficult to come by.
In the United States, around the time of the American Revolution, nails were scarce and many households had their own workshops for making them.
Because nails were so precious around this time, it was fairly common for some people to demolish or burn old or empty houses, to preserve the nails.