How you appear to others in Kingdome Come: Deliverance matters a great deal in terms of how you are received by characters in the world. If you fail to regularly launder your garments, heal your wounds and bathe, your Charisma will take a hit. The depletion of the stat correlates with how soiled your garments are, the severity of your wounds and the time elapsed since your last bath. Although you can usually get by when necessary without tending to these needs, you may find it difficult to persuade certain characters to see things your way; particularly guards and those of high social status.
Note: You can also use the bathhouse services to customise your appearance, currently limited to the options of stylising your hair and beard. Finally you can witness Henry timorously request a wench, and 'everything that goes with that', leading to a brief interlude which results in a +2 boost to Charisma (an option worth noting before any meetings with people in high places).