I had a mare who delivered on day 365 every time she was bred, like clockwork. The first year with her was a mare-stare from 'you know where' as I kept watching and waiting and watching and waiting and sleeping in the stall for seemingly months! Then on day 365 she produced the cutest little filly for me. Year two, I kept expecting that baby to arrive, and when after 3 weeks I was going crazy, I went back and checked my records, found she'd foaled the year before on day 365 so I took a break. Slept in the barn on day 364 and low and behold -- the next filly was born on day 365. After that, it was a no-brainer. I never got anxious until the last few days....360-365. Went on for several years, until I sold her.
A friend had bought her and she called me worrying because she hadn't foaled yet. I told her the history which made her a bit calmer....and on day 365 she foaled a colt.
So, I'm one that realizes they can go q-u-i-t-e a while before they show these little ones to us! LOL