The worst mistake I've ever made in an attic was doing cable runs (TV to the bedrooms) on a summer day in Texas. Sure, we started when it was cool at 7am... but

The worst mistake I've ever made in an attic was doing cable runs (TV to the bedrooms) on a summer day in Texas. Sure, we started when it was cool at 7am... but we finished around noon. So, to add to that: do it on a nice day in spring or fall.