I broke my own rule and didn't have a boost running when I selected the DC chest today. I got a Spend 2500 Tavern Silver task. No problem I think, that's the cost of a 24 hour Supply Boost, which is the one I buy anyway, but... big problem.
With my Castle now at an impressive level 1, I forgot about the equally impressive 1% reduction in the cost of Tavern Boosts. Meaning, I bought a 24 hour Supply Boost, thinking I would fulfill the task, but no! I'm 25 Tavern Silver short of the goal, with a 24 hour boost running. No DC today for me!
Break my own rule and it bites me in the behind. I won't be doing that again.