At the end of each session, characters earn XP:
At the end of each Season/Story Arc, all players may be grant 1 bonus XP. In addition, you may optionally vote as a group to determine which single character best expressed each theme used throughout the Season/Arc. Suggested themes:
This scale may be increased or decreased depending on the planned length of the campaign.
You can spend XP at any time, including in the middle of a session, but the advancement must be congruent with your behavior or training. If you've never picked up a sword, it doesn't make sense to gain Fencing; but if you took lessons or tried to fight with a sword stolen from a wall in a pinch in an earlier session, a single new rank may make sense.
Some Assets & Liabilities offer guidelines for story requirements in their descriptions.
A temporary windfall that allows you to make a certain number of purchases with a Cost higher than your Means (typically not more than 2 Ranks above the party median Means). Similarly, marrying above one's Class or Means may provide a temporary boost to those Ranks. Completing a Mission may provide access to an organization's Membership.