I've got 244,000 miles on the original fluid. If I had serviced the transmission every 60,000 miles (fluid flush and refill plus filter for proper procedure), I'd have about $1600 in maintenance costs so far. A factory re-manufactured unit for my vehicle is $2245 which comes with a three year warranty. So if I can get to 360,000 miles without a breakdown, I'm money ahead to not change fluid for sure.

The question really is would those 60,000 miles servicings get me much past 360,000 miles before a replacement is needed anyway?

2002 X5 3.0 244,000 miles
2004 325i 109,000 miles