I got dates mixed up once... no consequences from it, but it freaked me out. I tried hutch cards but could never get them to stay nicely in their little spot. Any amount of moisture in the air and they'd curl and fall to the ground. I have a binder in the house that has all of their info in it and a calendar, but that didn't help me when I was out in the barnyard without it...
So here's what I did that I am very happy with for now:
Went to the dollar store and bought a small white board for each doe and a sturdy little clamp to hang it on the front of the cages. In permanent marker I wrote their name, breed, birthdate, etc.
Then I labeled a spot (in permanent ink) for the date they were last bred, nest box date, due date, rebreed date and wean date. Since the boards are big enough, I have room to fill in the above info nice and large (with a dry erase pen0- easy to read from across the room, plus info about which buck they were bred to, how many fall offs, etc.
In the lower right corner I even write a countdown number (as in 2 for 2 weeks to go until their kindle date) so I can see which does are on their last week and I can give them an extra pinch of oats that week and get their nest boxes ready.
Since I added that little hack of an upgrade, I have felt much more organized and less stressed about dates. And once a month I just take my binder and a coffee down to the barn and jot all the info and notes onto each does page.
I figure if something happened to me it would be a lot easier for someone else to care for the animals, and for the animals that we share duties, we can leave each other notes. I am going to pick up another arm full of the white boards and make them for all of the various critters