A few on the boards will cash out as sson as they can. Look what is happening to some of the rewards programs and you can see why you may want to cash in as soon as possible. Another reason to cash in early...the program can increase the amount of miles, points or whatever you need to get an award. With that said I'm waiting to cash in on milesource...probably just nixed it for myself. Milesource doesn't take long and I'm fairly close to a large cashout anyway.
I hope this helps.