I've found that if I wait 20 minutes or so before jumping in the shower and shaving after I get up, it will stay smooth much longer in the day. Otherwise, if I do it right away, 10 o'clock tops. If I wait, usually good till mid afternoon.
It depends for me. If I shave with a brand new blade, it could last a day. If I shave with a blade that's been used a little, then about 10 to 12 hours. Of course it also depends on the time I took to prepare for the shave, and the quality of the preparation also.