“The opening of the trajectory correction thruster tube was originally 0.01 inches (0.25 millimeters) in diameter, and now it’s been reduced to 0.0015 inches (0.035 mm), or about half the width of a human hair, according to NASA.”
Voyager 1 has flown for 47 years on fuel lines that slowly clog with silicon dioxide. JPL switched thruster sets in 2002, again in 2018, and now back to one it already gave up on. To warm it up, engineers shut off the main heaters for an hour because the power budget cannot cover both. Every fix now borrows from something else keeping the probe alive.