In the latest issue of Consumers Reports, they rated smoke detectors and CO monitors. As it turns out, unless you have a dual sensor smoke detector, you might not have the protection (from fire) that you think. In short, one sensor is good at detecting flash fires and the other is designed for detecting slow, smoldering fires. To detect both types, you need a smoke detector that has both sensors. Two examples (that have both detectors) include the First Alert model SA302CN or the Kidde model P19000. Makes you wonder why any manufacturer sells single-sensor models when they know that it will cost some people their lives.
Likewise, as it turns out, some CO monitors work better than others. In fact, some don't work well at all. One model they did recommend was the First Alert model CO615. Again, why sell a CO detector that doesn't really detect CO? Since some companies can sell models that work as intended, why can't the others? After all, it is a matter of life and death. As for me, I'm going to replace my detectors tomorrow. No point in burning up or suffocating to death in your sleep if you don't have to.