Lots of variables of course, but three times the altitude (in thousands) + 10 with wind/weight considerations , as mentioned previously, is a good place to start.
Recall some years ago flying with a new First Officer who seemed to be obsessed with the proper TOD point.
Would twist the bezel of his Breitling watch for 15 minutes then announce proudly that the
proper descent point was xxx nm, precisely.
As it turned out, he was
precisely wrong nearly every time..
