1. The present Guide relates to the method and procedure according to which the period of validity of the verification of utility meters forming part of a defined lot is extended if the correctness of the utility meters has been proved by sampling inspections prior to the expiry of the period of validity of the verification. This is basically for utility meters used at private homes but with a sufficient number of instruments forming the size of a lot. 2. It is the responsibility of the national regulatory body to define the maximum permissible error (MPE) in service as a criterion of acceptance as well as the validity period of verification. 3. Only those types of utility meters that are subject to legal metrology requirements for the purpose of consumer protection are to be taken into account. 4. The sampling instructions applied have been compiled in the sampling plans (see Annex 2). They are valid for a limiting quality (LQ) of 8 % in compliance with ISO 2859-2 [1], thus corresponding to a consumer’s risk of 10 %.