This question already has an answer here:
One of my players is playing a Sorcerer who knows the sickening radiance spell (XGtE, p. 164):
When a creature moves into the spell’s area for the first time on a turn or starts its turn there, that creature must succeed on a Constitution saving throw or take 4d10 radiant damage, and it suffers one level of exhaustion and emits a dim, greenish light in a 5-foot radius. This light makes it impossible for the creature to benefit from being invisible. The light and any levels of exhaustion caused by this spell go away when the spell ends.
(This spell has a 10-minute duration and is a concentration spell.)
He has also chosen the Careful Spell metamagic option:
When you cast a spell that forces other creatures to make a saving throw, you can protect some of those creatures from the spell’s full force. To do so, you spend 1 sorcery point and choose a number of those creatures up to your Charisma modifier (minimum of one creature). A chosen creature automatically succeeds on its saving throw against the spell.
Sickening radiance forces creatures in the area to make a saving throw each round that it starts their turn in the area of effect.
If the Sorcerer wants their teammates to succeed on the saving throw against sickening radiance each round, do they have to spend a sorcery point each round? Or do the player characters get to pass the check automatically after the initial sorcery point is spent, since it was cast as a Careful Spell?