Most likely the rest of their life.

5000 IU is largely the minimum effective dose for supplementation. The FDA still recommends less than half of this, and it is a shame.

Disclaimer: I take 5k IU a day due to the past 2 decades of research on the efficacy.

I’ve been chronically ill for 11 years now. I wasn’t really exercising basically at all for 8 of them then I started walking 3 years ago and jogging 1 year ago and cycling 6 months ago. My VO2 max was 52 at age 24. 40 when tested a year later after becoming sick. I had it retested a year ago and it was 36.5. But I ran a 5:59 mile a month ago so it is very likely higher now. But I haven’t been able to get it retested since it is expensive. But my general health has massively improved in the past 6 months. I cycle 10-20 miles a day every day. I had like diastolic heart dysfunction and tons of arrhythmia showing up years ago and had a heart monitor redone this year and the rhythm is back to what it looked like before I became ill. I’m still sick but just seems like I have more vitality anyway now despite that.

A lot of times those 5% people go blind :/

Cars of any sort, self-driving or otherwise, do not solve traffic any more than Uber does because you need to have enough of them to get everyone to and from work at basically the same time. Trains are the only way to address traffic. Trains are self-driving. Europe already has the better self-driving system. It's just boring because self-driving is much easier when you build the road to support it instead of removing all constraints and adding GPUs, lidar sensors, cameras and an army of fall-back operators in overseas call centers.