Hirelings are always employed for a stated term of service or for the
performance of a specific task. Thus, a mercenary contracts to serve for one season. A
thief can be hired to steal a named item. A sage works to answer a single
question. A blacksmith may indenture himself for a term of years. A sailor works for
a single voyage. Quite often these contracts can be renewed without
difficulty, but the only thing that binds a hireling to the player character is regular
pay and good treatment. Hirelings do not serve a PC out of any great loyalty.

Thus there are some things hirelings will not do. Most hirelings do not
foolishly risk their lives. There are soldiers willing to take their chances on the
field of battle, but even these courageous (or foolish) few do not willingly
undertake the greater hazards of adventuring. They man castle walls, guard
caravans, collect taxes, and charge the massed foe well enough, but they often refuse
to accompany a PC on an adventure. Even a hireling who regularly undertakes
dangerous missions (a thief or an assassin, for example) normally refuses to join
player character parties. These hirelings are loners. They contract to do a job
and get it done in their own way, without interference from anyone else.

Hirelings are no more loyal than human nature allows. For the most part, if
paid and treated well, with opportunities to realize their ambitions, working for
a charismatic leader, hirelings can be relied on to do their jobs faithfully.
But poor pay, injustice, discrimination, threats, abuse, and humiliation at the
hands of their masters make them somewhat less than reliable. A smart leader
sees to the comfort and morale of his men before his own concerns. With less
savory characters–those hired to perform dark deeds–the player character takes
even greater chances, especially given the questionable morals of such
characters.

Whatever their personalities, hirelings generally need to make morale checks
(explained in the DMG) whenever they are faced with a particularly dangerous situation or are
offered a bribe or other temptation.

Finding hirelings is not difficult. People need jobs. It is simply a matter of
advertising. Under normal circumstances, applicants respond to ads. Only when
trying to employ vast numbers or hire those with unusual specialties (such as
spies) does the process become complicated. Just what needs to be done in this
situation depends entirely upon the DM’s campaign. Your character may have to
skulk through the unsavory bars of the waterfront, rely on questionable
go-betweens, or pay a visit to the thieves’ guild (if there is one). Just employing one
of these characters can be a small adventure in itself.

Employment costs of hirelings vary from a few gold pieces a month to thousands
of gold pieces for an especially dangerous task. The skill and experience of a
hireling has a great effect on his salary. A learned sage researching some
obscure piece of lore can charge hefty sums. Costs can also be affected by the
conditions of the campaign–the setting, the recent events of the world, and the
reputations of the player characters (if any). Most hirelings sign on for what
they think is fair. While few will turn down more money, most will drive the
best bargain they can. Your DM has more information about employment costs, since
he may need to alter these to fit his campaign.