Leaven experience - leaving longer than planned.
So I normally make a sourdough leaven one evening and then leave it to develop in the fridge overnight (8-16 hours, depending upon the recipe) and then use it to make bread the following morning. This weekend for various reasons I left it in the fridge for two nights! The following morning I checked it and it was still in good shape so I made bagels and ciabatta and there did not seem to be any adverse effects from leaving the leaven that long.
So if you need to leave your leaven for longer than planned it seems to can still make good bread!