As a relatively new e39 M5 owner going through baselining and putting his reference resources together, have to say your channel and format is great! Keep the content coming. Well done sir 🍻
Well for a sportier car that heats the fluid more often I like the 2 year interval. Same if towing a lot with a SUV or truck. Actually I’ll just say right around two years. It’s really cheap insurance that keeps corrosion out of your system and keeps your braking uniform. There are great simple testers as well like this one that measure moisture. amzn.to/3RFA0eH By reading moisture content you can be sure of the condition.