"if you can't handle the worst combat result possible don't attack".
This is very inportant rule. Early in turn risk of disorganizing your units is reason not to attack. Think about attacking USSR and disorganize your panzer spear head in East Poland on impulse 1. They will stay there until end of turn unless you use HQ to reorg them. IfHQ stay there, units can trace supply only 4 hexes from HQ.