There is no 10y rule, I also think many elders are too old and tired and certainly not motivated to watch over "lost" sheep for so long.
I can confirm however (like wasanelderonce said) that in my old cong there is this unwritten policy that it does matter if someone is still viewed as a JW by the general public. Smoking, celebrating "pagan" holidays etc. can still be a reason to be disfellowshipped.
I was damned lucky to already be left alone by the elders after 8, 9 months of my fade and 6 months after my last (fake) field service report. Not even an official invitation for the memorial.
I probably know too much and also their observation that we soon stopped praying might have left them with no hope... lol