[pclmulqdq]

One fun thing to do when designing high-precision analog stuff (audio) was to choose component values that are about 1.5-2% off of a value in the E12 series. You can then go test a whole bunch of resistors and you will find a lot within 0.1% of each other (even within 0.01%). Everything within 1% of E12 is binned as a 1% resistor so those aren't polluting your stock.

Going within 0.1% of an E12 value is a pricey resistor, but resistors that are matched nearly perfectly and are 2-3% off are cheap and easy to find.

[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.