The stock plugs are "single use" because the O-ring is glued in and not individually replaceable.
I think the Dimples all use crush washers, so the plug is reusable, but you might want to inquire about extra crush washers.
I've changed my diff oil once with the Dimple without replacing the crush washer. Doesn't leak.
Just found
this thread where I was agonizing over the lengths.
Trans plug was too
short, not too long.