CO-sensors: Cheap vs expensive, what's the difference?

[Daan]

I'm working on a DIY CO-sensor and coming across all different kinds of sensors (from MQ-7 to Figaro TGS5141, ME2-CO). I've read some posts here regarding the difference and it's mainly based on calibration. Other than that, is there a difference in accuracy, lifetime, temperature/humidity ranges etc?

[alowhum]

Another difference is digital bowl vs analog.

Analog is more sensitive and less susceptible to respond to other things (like volatile organic compounds). The downside is that it has will only work for a few years, since it has some material inside that slowly reacts.