Then the rest of the week, they can just go and do whatever at their leisure... Or do nothing at all.
I propose a randomized allotment per week, per character, to when they can take a job.
The intent here would be to incentivize people to be out and about more, hitting up various venues for work throughout the week, to spark things being more lively and also to prevent particularly cube-cozy people to hammer them all out in one go in the dead of night.
Possible ways this could be achieved is a randomized timer upon completion of a job. Weekly per character integers of X drugs, Y crates, etc.
This idea is far from crystallized, so feel free to pick it apart, but I do thing some variation of it (and variation in those jobs in general) would help from their supposed current standing as being gamified.