[e-khadem]

Raw room temperature value isn't the only reason we use precision resistors. Some parts tend to behave more linearly at higher voltages (especially at the Meg range) and others exhibit much lower tempco's. There is also the problem of long-term stability and value change due to exposure to high temperatures during soldering.

In any case, the above trick is neat, thanks for sharing it.

[amelius]

There are solutions to keep matched resistors at the same temperature.