[doru]

Last century when one used to buy a BMW from the dealership, one piece of advice was to use the "Eins Zett Gummi Pflege" twice/year. Then, the magic lifetime fluid started, and most of the common sense maintenance schedule was dropped in favor of the updated maintenance schedule.
So, if you don't want to replace the rubber window moldings, use the now new called "NextZett GummiPflege". It's still the old stuff, but I can vouch for it. I never had to change any of the rubber seals on any of my BMW's since before the turn of the century. The rubbers will never crack or cook even if the car is park extensively in the sun.
This is the webpage, but it can be found even on Amazon, I believe.

[Zajac1]

Good info

[YasF80_SLO]

Sweet tip man, seems like a solid product. Thanks for sharing

[lab_rat]

I use the Sonax brand Pfleger; it's great stuff I agree. I highly recommend its use on the rubber trim/seals.

[tlow98]

Love this stuff and 1z in general. Great products!

[Flyboy161]

Thanks for the advice. I'll be checking it out