Will is a resource for the players to manage like any other. They may spend as many points as they like to get the benefit they desire.
Keep in mind that Will is not easy to recover though - it refreshes at the beginning of the next job, not game session, and can only be recovered in play by putting themselves in trouble using their spots. As the Market, it is your responsibility to make sure they earn that point of Will. A Black Math cultist doesn't earn a point of Will just because he covers the crew's escape from a mob of casualties - he earns it because he blows an entire refresh worth of ammo on the first leg of a job picking off casualties that are no threat to the crew just to increase his k/d ratio, leaving him with low ammo for the job itself. A Taker with the Weak Spot of "Claustrophobia" doesn't earn a Will for being chosen to guard the outside of the mine shaft while the others check out the secret DHQS file storage site - he earns it after the aberrant is released and his crew is screaming for backup while he wastes two rounds standing outside making trauma checks to try and summon up the courage to go in and help his friends knowing that there are monsters in the dark and he is running right into its lair.
And remember: the Taker gets their point of Will after following their spot into trouble, not before - they don't get to have it to spend on the problem they caused.