The principal of "continued representation" in Legal Malpractice is that the statute of limitations does not start to run upon the making of a mistake,  while the attorney continues to represent the client.  "The statue of limitations sounding in legal malpractice is tolled until the completion of the attorney’s ongoing representation concerning the matter out of which the malpractice claim arises. Pellati v. Lite & Lite, 290 AD2d 544 (2d Dept. 2002).

Here is an example of a case in which there was no continued representation.  Mark v Dechert, LLP ;  2009 NY Slip Op 00437 ;  Decided on January 27, 2009 ;  Appellate Division, First Department .  The court does not explain why, but it appears that the attorneys represented the client in the run up to a merger, and then may have represented the entire entity, once merged.
 

In this case, "Plaintiffs’ legal malpractice claim is barred by the statute of limitations (CPLR 214[6]), which began to run in January 2000, when the merger of the corporate plaintiffs was completed and defendant law firm filed the merger documents. Even assuming plaintiffs could sustain their allegations that defendant represented them with respect to the merger, the complaint would have to be dismissed because their claim of continued representation is without merit (see West Vil. Assoc. Ltd. Partnership v Balber Pickard Battistoni Maldonado & Ver Dan Tuin, PC, 49 AD3d 270, 270 [2008]). [*2]"