2000 Chevy Malibu Driverside rear window regulator

Interior problem
2000 Chevy Malibu 6 cyl Front Wheel Drive Automatic

The window control cables have slack in them on one side of the motor or the other depending on the position of the window, and they came out of the guides. I put everything back and got the glass up after a while but don't trust the whole thing to work properly. I would like to know if this is normal for regulators to slack over time. And do you recommend I replace the unit if I'm not going to use the window anymore.( I unpluged the motor ) I'm hoping the glass will stay in place.