+1 on AZ_IPA's response.
It's done when you've had 3 consecutive identical gravity readings, usually taken 2 or 3 days apart, so a week to 10 days to confirm it's done.
Just don't forget, done is relative, because if it's too high, it's not finished, it's stuck.
If you do the usual stuff i.e. a bit of aeration, some nutrients etc, then the 14% ABV tolerance would be from 1.105 start to finish at 1.000 - about 105 point drop for 14 %, your start gravity is a bit higher so I'd expect some residual sugars.
So if you get a finished gravity of 1.010, then I'd consider it done/finished. Now I'd still cover my arse and stabilise it afterwards as some racking etc could re-vitalise the yeast a bit. There's plenty of people who say that they've got 71B to go higher than 14% and you don't really want "bottle bombs".....