If I'm using the compost for gardens, etc I wait a year, sometimes even two (sure is nice stuff after 2 years) but if it's going on hay fields it goes on pretty much fresh. This area is really unfriendly to organic matter and nitrogen (hot and dry), so I get better mileage out of it when it's fresh.
It's a bit of an art to get a compost pile to heat up nicely without overheating and drying out.. once it's dry, it's virtually impossible to get wet again (in our climate at least)... I like piling it, and about when it gets good and hot (about a week usually) I'll turn it to mix the outside layer in.. It's a smelly job, watch the winds!