Sometimes succeeding at a particular task requires a character to have a specific proficiency rank in addition to a success at the check. Locks and traps often require a certain proficiency rank to successfully use the
Pick a Lock or
Disable a Device actions of
Thievery. A character whose proficiency rank is lower than what's listed can attempt the check, but they can't succeed. You can apply similar minimum proficiencies to other tasks. You might decide, for example, that an electronic trap that uses a console requires training in
Computers to understand. An untrained
soldier can't succeed at the check, but she can attempt it if she wants!
For checks that require a minimum proficiency, keep the following guidelines in mind. A 2nd-level or lower task should almost never require expert proficiency, a 6th-level or lower task should almost never require master proficiency, and a 14th-level or lower task should almost never require legendary proficiency. If they did, no character of the appropriate level could succeed.