Myron Moskovitz

“Code of Civil Procedure §1161(2) prevents the landlord from claiming rent due more than a year before the service of the 3-day notice. See Fifth & Broadway Partnership v Kimny, Inc. (1980) 102 CA3d 195, 202. An argument could also be made on the ground of laches that it is inequitable for a landlord to wait a full year before demanding overdue rent. That argument was successfully made in Maxwell v Simons (Civ Ct 1973) 353 NYS2d 589, which held that it was unconscionable for a landlord to permit the tenant to fall more than 3 months behind in rent before bringing an unlawful detainer action based on the total arrearage. New York law required the tenant to pay the arrearage within 5 days or return possession. The court held that the landlord could base his eviction action only on the last 3 months' nonpayment of rent and would have to recover the balance in an ordinary action for rent. See also Marriott v Shaw (Civ Ct 1991) 574 NYS2d 477 and Dedvukaj v Mandonado (Civ Ct 1982) 453 NYS2d 965. In California, this reasoning, along with the cases cited above on "equitable" defenses, might be used to attack a 3-day notice to pay or quit demanding more than three months' back rent.”
― Myron Moskovitz, California Eviction Defense Manual

“No reported cases indicate whether a breach of an implied covenant of good faith may be raised as a defense to a residential unlawful detainer action [i.e., eviction]. Note, however, that a breach of the implied warranty of habitability may be so raised. See chap 15. It has been argued that the implied covenant of good faith requires a landlord to show just cause to evict a residential tenant. See Bell, Providing Security of Tenure for Residential Tenants: Good Faith as a Limitation on the Landlord's Right to Terminate, 19 Ga L Rev 483 (1985). If the landlord has breached the implied covenant of good faith, the tenant should consider raising that breach as an affirmative defense to the unlawful detainer action.
Because the courts have not yet decided whether the covenant of good faith applies in residential unlawful detainer actions, tenants must look to commercial lease cases for law concerning the covenant. Those cases have found an implied covenant. See §§19.20–19.24.”
― Myron Moskovitz, California Eviction Defense Manual