A Bright Wizard player in my group wanted to "refuel" Shielding Winds of Aqshy as he had a window of opportunity to do so and it was going to expire at the end of his turn leaving him vulnerable. Ie, it had 1 recharge token left on it.
After some discussion, I allowed it, but added +1 challenge die.
It worked out ok, but it set a precedent for refueling spells of that nature that give a benefit while recharging that is sure to come up again.
Does anyone see any inherent problem / game imbalance in allowing this?