To answer your question, we can't because we cannot remember all but two of our's birth/creation date.

Also as we grow we are seeing less importance in celebrating such things.

For me as a tulpamancer, I've made a habit of celebrating V's monthly anniversary of his creation.

I don't do anything crazy, but I try to give V some extra attention and do activities he enjoys. He loves watching movies, so I sometimes use it as an excuse to go out to see something in theatres

Our physical birthday is usually one of the worst days. Of the others, I only know one specific birthday, but don't celebrate it.

New on this sub. I don't believe anyone is created. People are reproduced, like all the living realm.