How often does an adventuring party avoid an encounter, even run away from one? This used to be common in earlier versions of the game, but less so now. What changed?
Do you ever have your character run away in video games? In most video games, because there's the "save game" mode, there's no incentive to run away. Try to beat the enemy, and if that doesn't work, respawn and either try again or wait until you're stronger. You can't do that as easily in tabletop role-playing games, where if you die, you die. (Well, most of the time . . .)
On the other hand, players from my campaign have been struck by how seldom other gaming groups actually gather intelligence, or run away. They'd learned not to fight every fight, not to jump on every random encounter, not to push beyond their limits while relying on the GM to bail them out. Fighting every encounter becomes habit with some players, to the point that they may characterize a too-tough encounter a GM failure, not their failure to recognize when they should bail out (or not even start a fight).
This is exacerbated by GMs who, if players won't take on an encounter NOW, will not let them take it on later when they're better prepared. In my opinion, this encourages foolish choices in a tactical-style game. It's OK when you play a storytelling game, where characters aren't really in danger unless the story requires it.
Perhaps another reason why running away is uncommon, is that there's work involved. Avoiding a too-tough encounter requires good scouting as well as good intelligence-gathering (such as interrogating prisoners). But poor scouting is not confined to RPGs; it was a characteristic of many ancient and medieval armies. Entire armies could be ambushed because of poor scouting (as Romans at Lake Trasimene by Hannibal). Roman and Macedonian armies at the Battle of Cynoscephalae marched along with a ridge in between, unaware of their immediate proximity despite earlier skirmishes near Pherae, until someone went atop the ridge and spotted the enemy.
I think part of succeeding, in military terms especially, should be knowing when NOT to fight. Think about combat odds from "Always tell me the Odds." If you recognize how dangerous combat can be, and avoid the most dangerous when you can ("run away"), you're actually helping out your GM, who has the difficult task of making combat feel dangerous without making it too dangerous!
Of course, in earlier editions of the game, one of the most exciting adventures was where you got lost. Then it's extra smart to avoid fighting. Perhaps if parties got lost more often, they’d be less in the habit of fighting everything. So what can a GM do to encourage players to avoid fighting what they should not?
“Run away, run away!” King Arthur, fleeing the carnivorous rabbit in Monty Python and the Holy Grail
Do you ever have your character run away in video games? In most video games, because there's the "save game" mode, there's no incentive to run away. Try to beat the enemy, and if that doesn't work, respawn and either try again or wait until you're stronger. You can't do that as easily in tabletop role-playing games, where if you die, you die. (Well, most of the time . . .)
On the other hand, players from my campaign have been struck by how seldom other gaming groups actually gather intelligence, or run away. They'd learned not to fight every fight, not to jump on every random encounter, not to push beyond their limits while relying on the GM to bail them out. Fighting every encounter becomes habit with some players, to the point that they may characterize a too-tough encounter a GM failure, not their failure to recognize when they should bail out (or not even start a fight).
This is exacerbated by GMs who, if players won't take on an encounter NOW, will not let them take it on later when they're better prepared. In my opinion, this encourages foolish choices in a tactical-style game. It's OK when you play a storytelling game, where characters aren't really in danger unless the story requires it.
Perhaps another reason why running away is uncommon, is that there's work involved. Avoiding a too-tough encounter requires good scouting as well as good intelligence-gathering (such as interrogating prisoners). But poor scouting is not confined to RPGs; it was a characteristic of many ancient and medieval armies. Entire armies could be ambushed because of poor scouting (as Romans at Lake Trasimene by Hannibal). Roman and Macedonian armies at the Battle of Cynoscephalae marched along with a ridge in between, unaware of their immediate proximity despite earlier skirmishes near Pherae, until someone went atop the ridge and spotted the enemy.
I think part of succeeding, in military terms especially, should be knowing when NOT to fight. Think about combat odds from "Always tell me the Odds." If you recognize how dangerous combat can be, and avoid the most dangerous when you can ("run away"), you're actually helping out your GM, who has the difficult task of making combat feel dangerous without making it too dangerous!
Of course, in earlier editions of the game, one of the most exciting adventures was where you got lost. Then it's extra smart to avoid fighting. Perhaps if parties got lost more often, they’d be less in the habit of fighting everything. So what can a GM do to encourage players to avoid fighting what they should not?
- Emphasize the mission. A random encounter along the way may be worth avoiding simply because it doesn't move the mission forward. Which brings us to...
- Give mission-based XP rather than XP for "monsters" killed. If you give XP for every encounter regardless of relevance to the mission, many players are going to fight every encounter just for the XP.
- Let interrogation yield useful information. Not every time, of course, but often enough that players will take prisoners, and even organize cutting-out expeditions to capture someone, in order to gather information. If interrogation never works, who's going to bother with prisoners?
- Don't let adventure publisher control how you GM the adventure. Modules tend to assume the party will fight whatever it encounters. You don't need to do it that way.
- Or at worst, let the party get their butts well and truly kicked a few times, and they might decide to pick and choose their battles.
Characters were easy to make, but we wanted to live and keep the progress we had made. We were invested in our characters, and we were wargamers before D&D. Retreating is a thing for situations where you have little to no chance of winning. There were plenty of tactics to help that. Caltrops, oil (burning or just slippery), pepper to interfere with scent hunters, dropping goodies (treasure or food). We were ready to dump wight / valuables if it meant moving faster and escaping too. And sometimes somebody acted as the rear guard. I lost a 4th level Paladin holding the rear against giant scorpions (post the Greyhawk supplement). I was the slowest (the joy of plate armor) and had a 2 handed sword. So, I yelled for everybody else to run. Just me, a 10' hallway and some angry scorpions. Poison was save or die in those days. Killed one of the beasts. Fourth round in I failed a save. Well, it was a heroic death anyway. And everybody else got away. My next character was a Thief. No heroics for a while. Until they decided I should "scout ahead" 
