I spent my Sunday as a grading panellist at one of our main annual shodan examinations. As I chaired the panel for part of the session, one of the other judges asked if I would talk to the candidates about our expectations for chakuso, or the way that we wear our clothing and equipment.
Lecturing dan grade candidates on this point may seem to some to be somewhat pedantic, but it is surprising to see how many people enter an examination without being correctly dressed. In some cases himo are miss-tied because of grading nerves, or the need to put equipment on quickly, but in many cases they are in the habit of doing it wrong. It really is important to wear your dogi and bogu correctly as this is a good barometer of your understanding of kendo etiquette.
Some frequent faults are that kote himo that are too long, so that either the kote fit incorrectly or there is a length of himo left hanging below the knot, dou and tare are worn too high or too low, hakama are too long or too short, or keikogi are either open at the neck or allowed to bunch up at the back. By far the most common error is to tie men himo so that the loops and the remaining ends are not of even length and that either or both exceed the regulation 40cm.
It is worth considering that not all men-himo are created equal. They come in lengths of 7 shaku (212 cm), 8 shaku (242 cm), or 9 shaku (278 cm). 8 and 9 shaku himo are for tying Kansai style men, where the himo are attached to the top of the men and cross at the tsukidate and again go through the top mengane before being tied at the back of the men. Obviously, if you tie these longer himo from the bottom of the men, they will leave an overly long surplus. On the other hand, 7 shaku himo are for some strange reason, just a bit too long to finish at the required 40cm. So whichever you buy, you need to shorten them.
Himo are expensive, so it seems a shame to cut them, but it is a must. Once you have done so, you need to tie-off or plait the frayed ends so that they do not continue to unravel. I have included an illustration from Kendo, A Comprehensive Guide that shows you one way to this.