It depends on what your weather is like and what it's likely to be doing in the near future.  Here, I usually put my beans in the bin, then run the fans for a day or two (or three depending on the bin) to cool them off once the weather cools down.  If it's really warm when I combine, I'll run the fan when I first get the beans in the bin, then again later when the weather cools down.  It's not unusual to combine beans in the 60's (F) or higher and you don't want those warm beans sitting in that bin when the weather cools down.  They will start to spoil for sure.

HTH,

Mike