If you agree to provide an essay for a collection of essays or a Festschrift please respect the deadlines which the editors establish. Taking said deadlines halfheartedly is a tremendous problem for those who are putting volumes together and strains nerves, hearts, and minds.
Would you allow your students to take weeks or in some cases months past course assignment deadlines to turn work in? I wouldn’t. You wouldn’t either.
So why treat your colleagues that way? If you don’t have the time, don’t agree to participate. If you agree to participate, make the time.
[Written on behalf of all those poor benighted editors who are crushed to the point of asylum despair thanks to missed deadlines and mountainous excuses the post-doc equivalent of ‘the dog ate my assignment’].
Grazie. Mille grazie!