When should I interchange my Wheels/Tyres?

Just taken delivery of my I3s and in the manual page 240 is says, "interchange front and rear wheels in pairs between the axles". This is sound advise but there is no indication as to what mileage this should performed at. Would say after 10,000 kms be a starter suggestion?
Assuming we are looking for the best practice or is there a preferred timeframe/mileage?

This only works if you have a 'square' setup where all of the tires/wheels are the same size. The majority of i3s sold have a staggered setup, so it won't work. But, if you do have a square setup, I'd consider doing it every 5k miles or so. With the torque of the i3, the rears tend to wear out first, so if you swap ends, then front and rear will tend to wear out at about the same time. It more depends on how you drive verses mileage. If you have a tread depth gauge, swap them when the rears get less than the front. Because of the torque and regen only work on the rears, they see more wear than the front on both accelerating and decelerating. In a 'normal' car, the weight transfer towards the front when braking tends to help even it out, but the i3 takes a double whammy on the rears, at least on a rear-wheel drive vehicle.

Like your i3S, the rear tires and wheels on our 2014 BEV are wider than the fronts.

In a left hand drive i3, the right rear tire seems to wear faster than the left rear tire. I plan to swap tires and wheels side to side on the same axle when I detect a difference in the tread wear rate. At 5k miles, I could measure no tread wear difference in the outer, center, and inner tread, so I did nothing and will check again at 10k miles. For this purpose, I bought an inexpensive tread depth gauge from Amazon.