No-one will have the same mileage out of a set of tyres as you: Some will get 5K, some will claim 20K. However, 10K from the 050As would be about average.
If they're under 3mm, I'd be changing them. Don't wait for a magic 10K to appear, just change tyres if they're worn, as this isn't the weather* to be eking about a few extra miles for the sake of it.
*Well, it might not be if winter ever actually arrives!