The person who keeps adapting should also be allowed to ask the plan to adapt.

Flexibility is quietly rewarded until it becomes an assumption. Whoever moves first moves again, and when the group hits another conflict, everyone knows where the slack will come from. It is not usually decided; it is inherited from the last time and the time before that.

If you have been the one adjusting, name it once, calmly, and ask for a turn rather than a favour. If you are the one who has been benefiting, offer the change before it is requested and see how much you have been receiving.