The tick bites

I already have the notorious 3.2 valvetrain ticking, this forum has quelled my fear about that I'm cool with it, but now I hear a new very distinctive clicking sound from the front, under the timing belt cover, and I know it must be that derned tensioner, my question is when do I need to get it changed out? From my records, the previous owners replaced the timing belt, tensioner, and water pump at 93,000 miles in '01 after hearing a clicking at the front. It now has 154,000 miles and I'm wondering if its literally a "ticking" time bomb as to when something will go wrong...