I worry about dates too, but I can't keep track of ALL of them..I will avoid immediate family's birthdates and any extended family's dates that I'm aware of.
Not because I actually care (they never gave a shit about me nor did they respect the reasons why I suffer), it's more so that I avoid having blame and excessive distaste thrown into the mix of my passing..also to eliminate the possibility of someone thinking my death had anything at all to do with them (so they can keep their mouths shut about it and not make themselves out to be some secondary victim of
my suffering, draw inaccurate conclusions, etc).
However, there are only so many days in a year and I'm sure my death will inevitably land on somebody's "special day" (which could be anything really)…after awhile, it becomes too exhausting to care.
I'll probably just leave a short note mentioning that the day itself has no significance and that if it does happen to coincide with anyone else's calendar moments, then it was completely unintentional.
For borthdays I would say now, there are birthdays all the time, it's not that big of a deal. I did make sure it wasn't near a big family wedding, for something like that it is best to avoid. That's my opinion, anyway. :)
I would avoid birthdates long before I gave a shit about somebody's wedding anniversary.