I’m lucky to get one clear day a month for the sole purpose of shooting street, so I’ve learnt to be more efficient when I’m under pressure and with strict time constraints. On a full days shooting, it's often the opposite - I’m happy to saunter about without the pressure of time hanging over me.
I am still focussed on shooting during longer sessions, but it's different...
I stop and grab a coffee, I wander, get some lunch and read my book, or grab a beer and look over the shots I've taken so far.
More time = less pressure = more relaxed = LESS EFFICIENT!