An article in The Tribune -- Write, review, update your will (by Staff Reports, 2/12/2022) -- gives important advice to anyone who has executed a last will and testament:
Share its location
A will is worthless unless it can be located and recorded at your death. Yet many people die with a “lost” will. Be sure to put it in a safe place, but also let someone else know where it can be found. Tell one or more loved ones or a trusted friend. Make sure someone knows where the original is kept.
Safekeeping your will is crucially important. Because wills can be misplaced and are "worthless" if misplaced, lawyers often offer to safe-keep the will for their clients. Another option in some jurisdictions, such as New York, might be to file the will in Surrogate's Court.
In New York, a lost will creates a rebuttable presumption that the testator revoked the will. Although rebutting this presumption is difficult and expensive, it is sometimes possible. NY SCPA 1407 sets the requirements for proving a lost or destroyed will:
1. It is established that the will has not been revoked, and
2. Execution of the will is proved in the manner required for the probate of an existing will, and
3. All of the provisions of the will are clearly and distinctly proved by each of at least two credible witnesses or by a copy or draft of the will proved to be true and complete.
So, in New York, a lost will might not be worthless, but it is definitely worth less since the procedure to probate a lost is time consuming and significantly more expensive than a typical probate.