36,000 Taliban Fighters = ? months of engagement

Assessing the militants’ numbers, General Barrons said: “There are probably 900 in the leadership, counting very junior to very senior, and there are between 25,000 and 36,000 people who would call themselves fighters.”

-London Times

So, at a breakneck pace of 1,000 a month (a figure I doubt we've ever achieved to date), it would be three years or thirty-six months to kill, capture, or convert (neutralize) all Taliban fighters.