Montblanc exchanges an unsuitable nib free of charge, provided the original nib is mint and the writing instrument is sent in together with the warranty card within six weeks; in older practice the period was 14 days. Without a stamped service booklet, sales receipt or invoice, the purchase cannot be proven; credit-card statements are not accepted as proof of purchase. A nib exchange outside the period is charged via the regular repair flat fee. With watches, deviations are often justified by Montblanc with the nature of mechanical movements, which also includes a certain tolerance in the GTC; warranty performance must, however, be provided. Goodwill is voluntary and not an enforceable claim; preventively the proper keeping of all receipts and being known to the local boutique staff is recommended.