My bike can take 40 with fenders, 45 without.

I use 32 or 35, either of which is more than adequate for crunching past any type of off road terrain.

I'm touring 99.8% on pavement, 0.2% off road. I'm not going to gimp myself with a heavier tire 99.8% of the time just to be more comfortable 0.2% of the time. That makes zero sense.