Every sensor stack has drift, noise, and operating limits. Premium components reduce those issues and document them, but they do not make readings absolute in every room forever. Confidence comes from combining vendor calibration evidence with software checks and sensible placement.
The SEN66 evidence set includes datasheet specifications, a sensor specification statement, and calibration collateral. Those documents define what the component can support under stated conditions. Field confidence also depends on airflow, dust loading, humidity, baseline exposure, and whether the device is placed where room air actually mixes.
Drift shows up differently by channel. CO2 can be corrected against outdoor-like baseline exposure. PM optics can be affected by contamination and aerosol assumptions. VOC and NOx indexes are adaptive by design, so their baselines are part of the algorithmic behavior rather than a fixed lab concentration.
Terrestream should communicate confidence explicitly: what is directly measured, what is indexed, what is contextual, and what the software is inferring. That is more credible than pretending every number has the same evidentiary weight.
