^If you proactively replace the window clips/sliders... the regulators can list pretty much indefinitely. It's usually the torque being applied in the wrong direction from broken components that breaks the pulleys or cables on the regulators. I don't know for sure, I'm pretty sure I'm still on factory regulators on 3 of 4 doors. I also don't usually see window motor failure on BMW's. Happens, but not often. The one regulator I had to replace I swapped the original motor onto a used regulator I bought for ~$30, threw on new clips/sliders, and a couple zip ties for good measure. Doubt I'll have to do the job again.

^But now that I've said that... LOL, it will break tomorrow.

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2005 X5 4.4i Build 04/05 Maintenance/Build Log
Nav, Pano, Sport (Purchased 06/14 w/ 109,000 miles) (Sold 8/15 w/121,000 miles)

2006 X5 4.8is Build 11/05 Maintenance/Build Log
Nav, DSP, Pano, Running Boards, OEM Tow Hitch, Cold Weather Pckg (Purchased 08/15 w/ 90,500 miles)

2010 X5 35d Build 02/10
Nav, HiFi, 6 DVD, Sports Pckg, Cold Weather Pckg, HUD, CAS, Running Boards, Leather Dash, PDC, Pano (Purchased 03/17 w/ 136,120 miles)