N.H. Rev. Stat. Ann. § 337-A:2

Unless a specific period is designated by law for their preservation, business records which persons by the laws of this state are required to keep or preserve may be destroyed after the expiration of 3 years from the making of such records without constituting an offense under such laws. This section does not apply to minute books of corporations nor to records of sales or other transactions involving weapons, poisons or other dangerous articles or substances capable of use in the commission of crimes.