Completely agree with Mal.

Over servicing with synthetics is a complete waste of time, and is bad for the environment.

Check your oil level regularly (as synthetic level tends to go down a bit) and follow MMAL intervals unless the vehicle is subject to extreme conditions.

They wouldn’t warrant the drivetrain for 10 years with 12 monthly/15k oil changes if they didn’t think it would happily go for twenty years.

And if you’re still concerned, get an oil analysis. That’s the best way to see if you need to move your intervals around, rather than just throwing oil down the toilet.

I also think use of overly thick oils is common place, the misconception appears to be a thicker oil will provide better protection. It absolutely won’t, unless there’s other issues. All you’ll do is piss more fuel away, and provide less lubrication at startup.