Honestly I’m leaning hard toward a mix of solutions:

1 skill and 1 talent from your tree every session.

4 each skill/talent ups, and an optional specialization tree change OR +1 to a stat, every new arc (4-5ish sessions), chunk-wise like Nicholas Hopkins proposed (that’s sticking with me). When I run a crawl, that’s when you’ve joined the rebels or discovered you’re force-sensitive or evolved your business from piloting to robbery, or whatever.