Everyone has to make a living somehow. Many games assume that adventuring PCs will make enough money off their various adventures to support themselves. They could do this either by collecting treasure and loot, or by accepting quest-like adventure commissions for a fee. If the king is offering 1000 gold pieces for slaying the dragon, that's as good a source of income as any.

But there's another paradigm that can be used: the heroes have regular jobs to pay the bills and adventures happen in their spare time. The GURPS roleplaying system notably uses this as its default assumption (although full-time professional adventurers are also supported). But playing a regular job is nowhere near as exciting as roleplaying the adventure parts, so GURPS provides the abstraction of a job table. This summarises the mundane jobs of the PCs - what they do and how much money they make each month. A single roll each game month determines if it's just a regular month, or if something exceptional happens at work that leads to a pay bonus, or perhaps an amount of damage from a work-related accident, if the job is hazardous.

At any rate, consider if your PCs make enough as full-time adventurers to live on, or if they should have other jobs as well.

Transcript

Han: Hey, everyone!
R2-D2: Hi, Jim. You didn't miss anything. The battle hasn't even started.
Han: I have some news. You know my post-doc expires soon? I've been applying for jobs and I just got two calls. Two offers.
C-3PO: That's great, Jim!
Han: But geophysics jobs aren't easy to come by. They're both overseas.
R2-D2: What? You can't break up our gaming group!
Han: That's not what I'm most concerned about...
{beat, shot of Leia}
Leia: Of course I'll go with you.
Han: Phew, that means I can accept one. I was afraid to ask, it's such a big thing.
Leia: Let's see. Dad's dead. I don't get along with my mother. And I'm a struggling actress.
Leia: Where we going?