Landed nobles - as well as wealthy guilders and clergy - have a retinue as part of their household, their personal retainers and associates that they maintain as part of their general living. For the nobility, this is part of the tangible expression of their living expenses.
For every five hundred firebirds a landed noble spends on living expenses, they have one household knight and his martial retainers - his squire or sergeants, perhaps a hobilar or valet - as part of their retinue. Each household knight has between one and five such retainers, usually averaging out to about three squires or sergeants for each knight of the household. In combat, these retainers count as veteran mounted riflemen and these household knights can serve as a single unit, or they can be sent out to augment other units as eyes and ears for their lord or as a core of elites.
Landless knights normally lack the ability to bring other knights into their orbit so easily, but they have their own retinue with one follower equivalent to a mounted veteran rifleman in combat ability for every 100 fb they spend upon their living expenses.
Powerful clergy also have their followers, primarily bishops who have at their 'disposal' one church knight for every five hundred firebirds they spend each year upon episcopal living expenses. While these knights are assumed to have attendant squires, these are not combatants. Cathedrals however provide a certain measure of additional military strength in the form of loyal faithful.
Wealthy guilders can be assumed to have their own security guards, nominally equivalent to riflemen though often armed less heavily and more competent as bodyguards rather than soldiers. Guilders have bodyguards based upon the size of their business rather than living expenses, gross income must be at least seven hundred and fifty firebirds a year and then they will have one bodyguard per three hundred firebirds a year gross, rounded up. Keep in mind that guilders can normally easily recruit bat wielding bully boys who are equivalent to militia for perhaps fifty firebirds a year per gang of fifteen or so, double this for full time professional thugs with armour and weapons.