Set the measurement
Move the gauge’s marker to the spacing you want and lock it before touching the cloth. Test the setting against a paper sample so an accidental slide does not repeat an error.
Choose a distance that belongs to the pattern and the thread. A precise measurement is useful only when the cloth can carry the resulting stitch field without puckering.
Use it for repeated checks
Place the gauge between marks, stitch starts or patch edges to keep the interval consistent. Do not press hard enough to stretch the fabric while measuring.
For a large grid, check the gauge against a ruler at intervals. This catches drift and confirms that the same setting is still locked after many repetitions.
Keep the tool clean and visible
Wipe away loose fibres and store the gauge with rulers rather than inside a thread bundle. The small slider is easy to lose when the tool is mixed with needles.
Record the setting in your project notes. A future border or matching patch becomes much easier when the original spacing is written down.