You change priorities then. If a set of features takes much longer due to whatever reason, you just pare them down or postpone release accordingly. If you have

You change priorities then. If a set of features takes much longer due to whatever reason, you just pare them down or postpone release accordingly. If you have important customers waiting for the release, you then first talk to them and then cut or postpone depending on their opinion and common sense. Delaying release doesn't summon demons or cause apocalypse, despite what some managers try to bs us.