Really depends on the cruising grounds. In the Greek Islands, the ideal seems to be to depart around noon and get where ever you're heading to by 3 or 4. Of course there's lots of swimming involved and the winds are their strongest in the afternoon. Sometimes, we have to bite the bullet and do a solid 10 hours simply because there just isn't anything inbetween here and there, but those are fairly rare.

15 to 25 miles or 3 to 5 hours of sailing a day is plenty enough for us.