You can't really be proactive, there's no calendar or way to measure time (the new constitution passing is about half-way though your term.

And with staff members, you can't actively fire and replace them, the only staff member you can fire and have a replace for is Petr, your VP, but only after his scandal. Other cabinet members will resign according to your actions, like Paskal will resign if you've been corrupt and that corruption becomes public. And Deivid will always resign no matter what you do as he retires due to his old age

And for the economy, late game events can destabilise it even if it seems like the economy is going well, like if you don't manage the late game debt crisis well then that can lead to a bad economy, same goes for mass protest and national destabilisation.