Time spent on PC maintenance

As a network manager, I spend a good deal of time putting out fires that would be mere smoulderings if I put in the time to run normal maintenance tasks on the PC’s like Win/Office/driver updates, disk checks, defrags, etc.
How much time do you spend a week on general PC maintenance? And if not, how much time do you spend a week putting out fires on PC’s?

Thanks for any input!
Susan