Summary
Whether yourDungeons & Dragonscampaign uses milestones or experience points for leveling, there are a number of ways that can get players to the next level. With experience point leveling, this is typically by exterminating anything that moves so that you can get that next spell slot or wild shape.
As a Dungeon Master, this can lead to some frustrating gameplay moments at your table if you aren’t rewarding XP for encounters not involving combat. While this can seem like a thin line to cross, there are a handful of non-combat encounters that are almost always worthy of a few experience points.

7Escaping From Prison
One of the more complex yet fun adventures your party can have is either breaking out of prison, or freeing someone else. This style of encounter carries a lot of risk and will likely go wrong at some point, but can be an exciting way for your party to solve problems outside of combat.
This can also be a way for them to be de-armed, and have to escape without using weapons, arcane foci, and thieves' tools. Although combat is likely in this scenario, if your players are able to successfully escape or break somebody out without a single alarm, that definitely deserves more than a handful of experience points.

6Giving A Rousing Speech
If your campaign is heavier on role-play, there will likely be a moment where your players are tasked with motivating a group of soldiers, calming an angry mob, or convincing reluctant villagers to take up arms. If a speech creates a turning point in the campaign, it deserves to be rewarded.
Especially if someone improvises an actual speech, rather than just rolling a Persuasion check, points are truly earned. Anytime your party actively takes steps to immerse themselves or the group in the campaign, they should be given more reasons to do so. If you feel it wasn’t a significant enough encounter for experience, you could reward Inspiration instead.

5Avoiding Combat
Just as defending a small town from a horde of gnolls rewards experience, finding a clever solution to avoid bloodshed at all should also be rewarded. This standard can help avoid your table fighting everything that moves to get that much closer to leveling up.
This can also be intimidating the bandit captain into leaving your camp alone, or redirecting cultists into a group of guards. Although it often takes much less time than rolling initiative and making attack rolls, it is a valid form of problem-solving that isn’t just prioritizing violence for the sake of experience.

If enemies decide to run away from combat, players should get experience points for those creatures as well.
4Escaping A Chase
Chase scenes in D&Doften resemble a pirate ship sailing in your wake, guards chasing after the party rogue, or a dragon preparing to burn you to a crisp in an open field. In scenarios where you’re likely to fail, running is always an option.
If your party begins a chase scene and succeeds through a number of various checks and spells, then that ordeal should reward them with experience points. However, if they get caught, or escape with barely a handful of hit points, consider it a failed encounter.

3Ending A Long Journey
Especially at lower levels, some campaigns will have the partytraveling across vast distancesto reach important locations, people, or pieces of lore. Although the journey will likely have them fighting in plenty of combat encounters, the journey itself should be considered an encounter.
It is also a good way to punctuate the end of the journey, as you describe the glimmering city gates, and your players level up at the time. This is a mechanical way to validate the dangers and effort the journey required while getting them closer to the Teleport spell.

2Completing A Personal Quest
Although not required for a campaign, even a great one, a player witha detailed backstorycan help them feel immersed in the setting and gameplay. Often included in backstories is a personal goal that the player wants to accomplish specifically for their character.
This can be vanquishing a nemesis, finding a lost family heirloom, or reuniting with a lost love, and can sometimes take an entire campaign to complete. Although it is a singular goal in a collaborative game, a member of the party completing a personal milestone is worthy of experience points.

1Solving A Mystery
Pointing the finger at the murderer at the dinner party, unmasking the cultist who was slowly taking over the church, or discovering the hidden werewolf in the village are all examples of a good mystery. Rewarding experience points for these kinds of encounters should relate to how difficult it was to solve rather than the outcome of solving it.
While finding a letter in the satchel of a bandit directly telling you who killed who solves the mystery, it isn’t worth potentially leveling up. Overall, a challenging mystery encounter should take more than a couple of ability checks to solve. Granting experience points this way can also help avoid the feeling like time was wasted if the villain escapes.