--Bona al la encycla lorica.
Standards of Entry
The guilds make regular membership (as opposed to indentured membership) in their guild a precious thing, and set a high bar for entry into their guild. After all, as monopolies, all the guild members have an interest in keeping the guild lean, so that there are fewer people to divide the up the proceeds among. Also with a smaller membership it becomes easier to determine who leaked a secret as it is easier to keep tabs on where everyone is and what they're all doing.
A person can only ever join one track - spellcaster, spellcrafter, spellshaper. However, the distinctions between the three are not made apparent to the initiate and new members are not told which section of the guild they'd be joining.
Entry to the guilds is generally a year-round activity; there are no distinct classes per se, but instead they will have mentors. This is because each guild hall trains its own initiates and is actually quite small.
Membership in all the guilds is for life. This applies even in the case of spellshapers, where they were still young children them their parents offered them to the guilds; which means that for them, their lives are pledged to the guild and they have no say whatsoever. It also applies to those forced involuntarily into the guilds, thereby trapping them for the rest of their lives. The United Guilds ensures that members of one guild cannot transfer to another guild should they become disillusioned or find their environment intolerable.
Most states (all except those with poor relations with the guilds) have the understanding that members of a guild belong to that guild, and any falling-out is between them and their guild, with the state not intervening in the matter. In practice this means gives each extensive control over their members, especially by masters over all the guild members that report to them, since their masters control their fates, such as promotions or transfers to other guild halls, projects and responsibilities, punishments, etc. This imbalance of power means that the associates in guilds often become victims of harassment and abuse - verbal, emotional, physical, sexual - and though concerned guild members may form intra-guild orders to try to deal with the issue, accusations are relatively rare due to fear of reprisal as generally guild members cannot escape their immediate colleagues.