As students of Spanish, we generally learn (at least I did) that deber is used in the conditional to mean "should" (debería). But as the below example demonstrates, and I've seen it countless times now, deber can also mean "should" even when it's not in the conditional:
- No he debido deciros eso (I shouldn't have told you that).
I am wondering if anyone could lay out some ground rules on when the conditional form would be used here (as in: No debería haberte dicho eso)?
EDIT: Since it has been requested, here's another example:
- "No debí haberle hecho caso a Esteban" = I should not have paid attention to Esteban.