For cards with Accelerate, do you have to pay the Accelerate cost when playing/summoning the unit, or can you pay it later in your turn?

Ruling: When you play a unit with Accelerate, you may choose to pay the Accelerate cost or not at that time. You cannot pay the Accelerate cost later in your turn.

Sequence:

• When playing the unit card, decide whether to pay the Accelerate cost
• If paid, the Accelerate effect occurs as part of playing the card
• Once the unit is on the board, Accelerate can no longer be paid

Nuances:

• Accelerate costs can only be paid as part of the steps of playing a card, not while the unit is on the board