When the party fails.
Why not, instead of just saying "try again," have some detailed description of what happens when you fall in battle. You know, something specific to that scenario. For example: You are felled by an Ash grue. Give some sort of description of the aftermath like in the old Fighting Fantasy games.
Just an idea.
Aaron Abenoja commented
Wait, like in Diablo 2? so that if your surrounded or killed instantly then you get a message saying that you fell due to this creature doing this attack, okay I may have added "this attack", but I would also like to know what had happened to me and my party each.
that seems interesting