This really isn't groundbreaking, but I was looking for a case on this issue the other week and couldn't find a recent one. So I'll just leave this here.
CPLR R 3025 Amended and supplemental pleadings
Jenal v Brown, 2011 NY Slip Op 00487 (App. Div. 2nd, 2011)
While leave to serve an amended pleading should be freely given upon such terms as are just (see CPLR 3025[b]; Edenwald Contr. Co. v City of New York, 60 NY2d 957; AYW Networks v Teleport Communications Group, 309 AD2d 724; Charleson v City of Long Beach, 297 AD2d 777; Holchendler v We Transp., 292 AD2d 568), leave should not be granted where "the proposed amendment is palpably insufficient as a matter of law or is totally devoid of merit" (Morton v Brookhaven Mem. Hosp., 32 AD3d 381, 381; see Thone v Crown Equip. Corp., 27 AD3d 723). Here, the proposed amendment was clearly without merit as the plaintiffs' motion was made nearly one year after the statute of limitations had expired, and there was no basis in the record to support a claim that the Town of Babylon should be estopped from relying upon the expiration of the statute of limitations (see Luka v New York City Tr. Auth., 100 AD2d 323, 325, affd 63 NY2d 667; Yassin v Sarabu, 284 AD2d 531; Nowinski v City of New York, 189 AD2d 674, 675).
Schroeder v Good Samaritan Hosp., 2011 NY Slip Op 00500 (App. Div., 2nd 2011)
Where, as here, a summons and complaint are timely filed but not served, service of a substantively similar amended summons and complaint without leave of court under the same index number is proper when it is served "before the period for responding to the original complaint has expired" (see O'Keefe v Baiettie, 72 AD3d 916, 917, citing CPLR 3025[a]). Thus, the Supreme Court obtained personal jurisdiction over the defendants because they were served with substantively similar amended pleadings during the 120-day period when service of the original pleadings was required under CPLR 306-b (see O'Keefe v Baiettie, 72 AD3d 916). Moreover, under the circumstances, the action was timely commenced as against the defendants.
The bold is mine.