 Users are often cautioned not to lend or borrow fountain pens as the nib "wears in" at an angle unique to each individual person.A different user is likely to find that a worn-in nib does not write satisfactorily in their hand and, furthermore, creates a second wear surface, ruining the nib for the original user.This, however, is not a point of concern in pens with modern, durable tipping material, as these pens take many years to develop any significant wear.