Some skills (such as Cooking, Swimming, Lovecraft, or any Combat Skill) explicitly state that they are automatically opened at OML when the skill is attempted for the first time. Language skills can be automatically opened after constant exposure to it for a month. There are no explicit rules for opening most other skills. It is reasonable to assume that the amount of time it takes to teach these skills will vary from a month to many months, depending on the difficulty of the skill. Certain obscure lore skills and difficult craft skills take the longest to learn (that is, to open at OML). Teaching requires a teacher of decent skill and access to the tools or texts as appropriate. Self-teaching is possible with access to the tools or texts and lots of experimentation, but will take much longer (at least three to five times as long). However, the tools, texts, and techniques of many crafts and lores are held as guild secrets, so self-teaching the most difficult skills may take many years