Apprenticeship periods vary in length and are either concluded by the permission of the Guildmaster or by the acquiring of a level of proficiency in skills (if auto-assent is on).
Your stature within your guild is as important as in any another situation. When you are first admitted to a guild you will find yourself under an apprenticeship. This will change as and when you and the Guildmaster are both fully sure of what the guild and your character have to offer one another. Apprenticeship is ended by mutual consent between Guildmaster and apprentice, or by surpassing the minimum requirements for auto-assent to full guild membership (typically three Grand Master or two Legendary level skills) in those guilds where such an option is available. Auto-assent is obtained from the guild tutors by typing COMPLETE APPRENTICESHIP.
Beyond your apprenticeship, you will become an ordinary guildmember (of the guildrank Initiate), whereupon you may learn of all the skills that the guild offers you with no obligation to do any more than defend and uphold its prime interests
While you remain an apprentice you will not assume the profession of the guild and will be free to QUIT GUILD and choose another (losing that guild's skills but gaining those of another). However, once you chose to end your apprenticeship, you will gain the profession of the guild and will thenceforward only be able to join guilds associated with that profession. When a non-apprentice quits his guild, he may retain the skills he has developed. Apprentices may KNOCK on the guild door to call out the secondary guild tutor for learning lessons - something to be borne in mind when a member of a security conscious guild loathe to give out keys to vulnerable young members.