Hey there! That's a really smart question - it's easy to get excited about the 24/7 production potential of lights-out factories, but the maintenance side can absolutely make or break the whole operation. Based on what I've found, here are the most commonly overlooked challenges that could turn your automated dream into a maintenance nightmare:

1. **Specialized expertise gaps**: When everything's automated, you can't just have a general maintenance tech walk in and fix things. Robotics and advanced automation systems require specialized training that many plants underestimate. You'll need technicians who understand both the mechanical and software sides of your equipment.

2. **Predictive maintenance dependency**: In a 24/7 operation, you can't afford unexpected downtime. The problem is that many companies think 'automated' means 'maintenance-free.' Actually, you need MORE sophisticated predictive maintenance systems to catch issues before they become catastrophic failures. Without this, one small problem can cascade through your entire automated line.

3. **Software and firmware updates**: People focus on hardware maintenance but forget that automated systems run on software that needs regular updates, patches, and compatibility checks. An outdated software version could bring your whole factory to a halt.

4. **Remote monitoring limitations**: While remote monitoring is great, some issues require physical inspection. If your monitoring systems aren't comprehensive enough, you might miss subtle signs of wear and tear that a human would notice during a walk-through.

5. **Supply chain for specialized parts**: Automated systems often use proprietary components that aren't available off-the-shelf. If you don't have a solid spare parts strategy, you could be waiting weeks for a replacement while your factory sits idle.

6. **Integration complexity**: When multiple automated systems from different vendors need to work together, maintenance becomes exponentially harder. A failure in one system can affect others in ways that are difficult to troubleshoot remotely.

The key is to remember that lights-out doesn't mean maintenance-free - it means maintenance needs to be smarter, more predictive, and better planned than ever before. Companies that invest in proper training, advanced monitoring systems, and strong vendor partnerships tend to avoid the nightmare scenarios!