30km limit

I noticed that every 30km of walking or biking one of my legs fails. Question: compute the maximal distance $x$ I can cover by walking or biking.

I intended to get back by train. However the sun deterred me by holding me in trance with its magnificent display of sunset.

Bus services replaced train service after dark just for this month. The buses are without bike racks. It is illegal to ride after dark without reflectors. My bike is not equipped with reflectors. Also my mileage (or is it kilometreage?) is very close to $x$. How did even I managed to get back?

Conjecture: the screen distance I covered by painting or taking notes also just exceeded 30km.

We always recover after enough rest???