What's your take on baby monthsaries? Do you think it's necessary?

It really depends on your values and how you do celebrations in the family. In our family, we did celebrate the first 12 months of our 2 kids every month with a cake and a simple celebration as a form of thanksgiving for the gift of life. We would also take photos of the babies and compile them so that when the baby reaches his 1st birthday, we include the compilation of photos in the party set up.