I put 'generally within a day or so' by which I meant, I tend to realise a day or two before it comes that it's going to show up. I get crazy mood swings and feel very depressed a day or two before, and sometimes get cramps as well. On the odd occasion I don't have those 'symptoms' I'm surprised.

I don't track cycles or make marks in a calendar or anything. This is Wrong? isn't it? I can usually remember how long ago my last one was, and they turn up every month, but that's as precise as I get.