[Alleyfield]

I understood that he meant being in a bus/train/van-pool/subway/ferry. The point that I was trying to make was that trying to do "something useful" while commuting is, at least to me, pretty annoying - there's so much distraction going on around you that your chances of actually having attention to the task you're doing are slim.

And time without attention is time wasted.

Ultimately you might find yourself using 24/7 of your time in practicing things - and realizing that you've understood nothing.

And then you're ready to welcome the burnout

[drKarl]

Yes I meant a bus/train/van-pool/subway/ferry, and yes I was thinking in listening to an audiobook/podcast, reading a book, perhaps doing some brainstorming with a Moleskine (well, it depends on the crowdiness of where your are), and if you have a table perhaps working on your laptop...