The obligation to repair common elements is a frequent source of dispute between boards and individual owners. The business judgment rule applies to both residential cooperative corporations and to condominiums. Levandusky v. One Fifth Avenue Apt., 553 N.E.2d 1317 (1990); Perlbinder v. Bd. of Managers of 411 E. 53rd St. Condo., 65 A.D.3d 985, 989 (1st Dep't 2009). However, the business judgment rule "will not serve to shield boards from actions that have no legitimate relationship to the welfare of the [cooperative or] condominium, or that deliberately single out individuals for harmful treatment." Perlbinder, 65 A.D.3d at 989.