Don't. A cable under tension on a torsion system can take a finger or worse if it slips while you're working near the drum, and the spring behind it is storing enough force to do real damage. This isn't a judgment call the way choosing a paint color is - it's a mechanical system under load, and the failure mode is sudden, not gradual.
What you can safely check yourself: look at the cable where it wraps the bottom bracket and the drum. If you see fraying, rust, or the cable sitting off the drum groove, that's your answer - call it in rather than run the door. Given the income level and the newer housing stock in Keller, most of these calls end up being a cable-and-balance job, not a full system replacement, but we won't know which until we're looking at the drums in person.