So I've been harping on bad delver-hireling relations for a few posts.
How about good delver-hireling relations, codified into rules? Here are two more optional expansions to the Loyalty rules.
Note that Dungeon Fantasy 15: Henchmen already covers a fairly large swatch of good treatment. Successful delves, pay above scale, rescue, etc. Players who hire help would do well to read Loyalty, DF15 p. 30 and do those things. It takes consistent effort and good deeds to build up trust over time, but bad treatment tends to inflict permanent damage on the relationship rather quickly. Hirelings tend to think you are how you act on your worst day.
Gearing Up. Permanent purchases and gifts of new equipment to a hireling should be treated as pay increases equal to 1/2 the value of the gear. (That is, it's slightly better than the sale value of the gear, but people prefer cash bonuses to "Here is this shortsword I found, keep it.")
Trust. +1 to +3 temporary loyalty. Demonstrations of trust can cause temporary increases in Loyalty. These include trusting a hireling with a valuable and/or mission critical piece of equipment, loaning a powerful magical item, or putting your life in the hireling's hands. Assigning jobs that require trust may qualify in some cases. Such circumstances need to be exceptional - the GM should decide if the task is important enough and the hireling would recognize it as a matter of trust and not just palming the job off. At the end of the session, roll a Reaction Roll. On a Good or better reaction, the hireling's Loyalty increases by +1 permanently.
Trusting a hireling with an important job, handing them the Wand of Orcus to use for the session, and otherwise demonstrating that he is in a position of trust and respect may translate to better reactions in the long run. Of course, some NPCs aren't worthy of such trust, but then again, some PCs aren't, either . . .