There is a six year statute of limitations on claims to recover a debt under a written contract such as a promissory note. Failure to file suit to collect the debt by this deadline results in the claim being time barred. However, in some cases, this can be extended if the debtor acknowledges in writing the debt is owed before the six year statute of limitations has expired. The following quote from a 2001 case explains how this works:
The Wengers next contend that their letters requesting an itemized bill are too vague and therefore not effective in tolling the statute of limitations. When a writing is made before the limitations period has expired, any acknowledgment of the obligation necessarily implies an agreement to pay, unless something in the acknowledgment requires a contrary conclusion. An effective acknowledgement must either expressly promise to pay or acknowledge that the obligation exists. Either is sufficient, but it need not contain both. If the writing contains the latter, it must express a clear admission of the debt. Moreover, it must be communicated to the creditor and not indicate an intention not to pay.
Fetty v. Wegner, 110 Wash. App. 598, 36 P.3d 598 (2001) (footnotes omitted; quotation marks added).