As a rule of thumb, I'd say one cliché per [Romance]--and then be damn sure you can make it work. But if you're going to try to write the virginal amnesiac twin disguised as a boy mistaken for the mother (or father depending how well the disguise works) of a secret baby, honey, you better have some serious skills. Or seek therapy.
Nora Roberts
beyond-heaving-bosoms, cliche, romance