Of XP and Leveling

I will start by saying, I don't like Milestone leveling. I get it, in theory, but for my playstyle I prefer XP. If I were playing a detective type campaign or something more narrative driven, I would most likely use milestone due to the lack of combat (usually).

Below is how I usually factor XP in solo play

Quests

Quests are a bit tough for me but I am able to take a few factors into consideration when doling out XP for quests. As a practice, I will give all quests a base of 10-25xp depending on aforementioned factors. Which I will go over here. Now. Down below. Yeah.

1. Quest type - if the quest is just an in-town quest asking a bunch of questions or investigating something I will usually do a base 10xp + 5xp for any relevant information gathered. Sometimes these quests can yield upwards to 50 or more xp once its officially closed. On the other side of it, an overland quest like delivering something between cities or exploring a particular region, then I will award a base of 50-100xp with an addition 5xp for anything interesting or relevant information.

2. Difficulty - if a quest is taking my PCs into a dungeon or abandoned castle full of peril and unknown danger, I would consider that very difficult and offer a flat 100-300 or so xp plus the additional 5xp upon closure.

3. Length - Lastly, if a quest's length is going to be quite long and obvious from the beginning (i.e. a local Lord asks you to travel to the next continent, learn all you can about a city, and report back after some time), then I will give it a large XP yield upon completion.

Combat

This one kind of speaks for itself, I award standard amount of XP per foe defeated.

Daily

At the end of the day, I will award the PCs 75-100xp at the end of the day, depending on how eventful it was.

Skill Challenges

Occasionally great feats of skill will come up. Maybe the PC had to sneak through a patch of flowers that, if disturbed, causes the PC to fall asleep for 1d6 hours with a failed Con save. Even if they stumble a few times but ultimately makes it through, I will award XP for that, as well.

Feel free to incorporate these into your house rules!

Happy Adventuring!