I know my wife's '88 BMW recommends time or milage whichever comes first. In that case they are recommending 5 years as the maximum as I remember. That is coupled with a milage of about 50K miles.

Based on that, I would say 7 years on your '95 960 should be a maximum time. If you live in a hot climate area maybe less? The belt is so easy to change, (my first time was only 2 hours), I'll bet an experienced mechanic does it in an hour. Therefore the cost to replace is so low, just change it and then relax. Especially compairing it to the cost, if it breaks!

I hit the 70K mark on my 96 over a year ago so I will continue to use the 70K parameter.
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'96 965 at 89K. Had '85 745 Turbo Diesel for 200K.

I would pick 40,000 in your case that puts you around 7 years, in my case I'm doing it at 60,000 not taking a chance, replacing tensioner, Timing Belt Idler Roller and water pump every other.
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1996 960 124,407

In the past 2 monthes I've seen 2 960 belts snap before they hit 70k. They both had original belts and were low milage for their age. Both got new heads due to bent valves. Not an easy job to do without special tools.

I changed an original belt on an 83 245 in 2000 @ 49000 mi. It could have gone longer. As long as i'ts not oil soaked change it at 50000.

Mark

Rubber does crack and is subject to deterioration from heat, ozone, underhood chemicals, etc. Given that the cost of a belt failure is catastrophic, I would recommend that you err on the side of caution and change earlier than 70k miles. The average mileage incurred by users today is about 15k per year, so 70k would be equal to a little over four years of use. I would think that in your case an interval of 40-50k miles would be fine for your belt (six to seven years).