First the minimum time: - audiobooks while commuting (mostly walking to work). Even if it's like 30-40 minutes some day at most, it still adds up. - add to that lets say ~15 minutes each night before sleeping.

And on top of that: - sleepless nights, when you want to get back to sleep: 30 minutes - ... - just having a good series to grind through. - audiobooks during some manual labor (home restoration works for example).

So for me audiobooks + capability to read at night without disturbing others (dark mode + backlight on e-reader). And from that it adds up.