Skill Familiarity

Repair does not have specializations, but it does have familiarity. Technically all skills do, but I wanted to expound upon it for Repair.

When you repair something similar to something you've repaired before, there is a -1 penalty and it takes twice as long. ex. A home hobbyist car mechanic that's only ever worked on their own truck who then tries to work on a mid-sized sedan. Typically this can be overcome after doing a single repair.

When you repair something you have theoretical knowledge about, represented by another skill, there is a -2 penalty and it takes twice as long. ex. A car mechanic with some training in Science (Engineering). Typically this can be overcome after doing an extended period of work or research on the topic. The time will vary, but a month is a good baseline.

Repairing something you have absolutely zero experience or background knowledge with sits at a -4 and takes quadruple the time. A car mechanic with no other training attempting to repair an industrial heating system. This cannot be overcome by time and will require taking the at least a d4 in the relevant skill / specialization.

Technical documents or manuals, such as a car repair manual specific to the model you are repairing, can half the penalty time, or reduce the penalty by 1.