Executions, once recorded, continue as a lien for six year. In this regard, they are governed by G.L.c. 236, §49A. That statute also provides that executions can be brought forward (extended) for successive six-year periods in the same manner as attachments are brought forward or extended under G.L.c. 223, §114A. The extension must be filed before the six-year period has expired. It is important to determine how each registry documents these extension so that the examiner can check the appropriate records to see if an extension has been filed..
Also, if the sheriff conducts a sale during any of the applicable six-year periods, G.L.c. 236, §27 provides that the sheriff's deed shall bind all parties "if recorded within three months after such sale." This, of course, means that the six-year period is really a six-year-and-three-months period. In other words, even if an extension has not be filed within (during) the six-year period, the title cannot be safely passed until three months after the six-year period has expired. See REBA Title Standard No. 47.
Sometimes confusion seems to creep into discussions concerning the expiration of the lien created by an execution. In some cases I've heard it suggested that the lien has a period of twenty years. A judgment is good for twenty years. It's possible for the lien of the execution to continue even beyond that point if extended repeatedly, the initial period of the lien of the execution is six years.