In the FAQ, a point says
Choices Matter. Your choices have consequences. (...) If you roll too low on a Combat check, it’s too late to play a Strength spell to improve your result.
Does that mean I have to play all the 'discard this card to add a die to a check' cards before attempting the check? E.g, I'm doing some combat check, I need 8 to beat it. I roll my hand-to-hand combat strength check, and get a 6. Can I now discard a BotG to add another die to the result, and try to beat the test?
Or would I have to specify before the check that I would discard the BotG to get an extra die?