Holiday custody schedule - need to vent

Our custody agreement says we "alternate major holidays" but doesn't specify what counts as major. Christmas was mine, she wants Thanksgiving. Fair enough. But then she's also claiming New Year's Eve/Day as separate holidays that should be hers too?? And wanting to do Christmas morning with the kids even though I have full Christmas. This is the fourth year of this and I'm SO tired of renegotiating. Do I just need a lawyer to nail down every single date in advance or am I being unreasonable?