Post my Christmas reading (Waterloo Rout and Retreat by Andrew W Field), I've been thinking that we sometimes underestimate the importance of retreating. Being able to break contact, rally and regroup is often the key to later strategic success.
The hundred days campaign contains both good and bad examples:
Blucher on the 16th/17th
Wellington on the 17th
Napoleon on the 18th/19th/20th
Grouchy on the 19th/20th
What aspects do we think contribute to a successful outcome, or lack of it?