How skills work is of course a much-chewed-over topic here on Yoggie. The BRP system is inclined to be somewhat swingy, and while usually more or less fine for the rules-light game I want, it sometimes produces results that feel unsatisfying. The most common of these are when characters who are skilled professionals nevertheless fail to do something that's part of everyday routine in their profession.
To be more specific, this usually means the character is attempting something their profession requires them to do regularly and reliably, and there is no active opposition to their efforts.
Let's take a detective for our example. Jane Blunt has been walking the mean streets for ten years after another ten on the force. Asked to investigate SusCo, she walks around the site looking bored and carrying some forms, occasionally peering at guttering. When someone slips out of the fire escape for a fag break, she calmly steps inside. Is this legal, wonders the player?
* Jane rolls Law. Assuming she has a 70% in Law, there is a 30% chance she can't remember the laws applicable to gaining entry to a premises, even though that's pretty fundamental to her job.
Jane wanders into the office of Theo Cashfist, the corrupt director of the firm. Before waiting patiently in his chair with her feet on the table, she examines the paperwork.
* Jane rolls Accounting. Although she spends hours every day discovering people's dirty secrets by reading their paperwork, with a 70% in Accounting, 30% of the time she won't notice that money is being siphoned out of the company into Cashfist's account.
Similarly, we have the expert medic who repeatedly fails First Aid rolls to apply bandages, the professor of art history who can't spot a Van Gogh in a pile of dross, the occultist who mysteriously misses all the satanic references in The Satanist's Little Book of Satan References, and so on and so forth. Of course, all this depends on just when the Keeper chooses to ask for a roll, which is a big question.
I tend to be a bit lenient for the sake of verisimilitude, so generally I just won't ask for a roll if when I think the character concerned shouldn't have a realistic chance of failing at it. If there is an actual doctor in your party, they should be able to splint your leg providing there are no other deleterious circumstances. If a private eye searches an office for handguns without any time pressure, unless the handgun is somewhere truly bizarre, they should find it. If a police officer is challenged on the legality of an arrest, they should know the answer (no matter what answer they actually give).
If you wanted to mechanise this formally, there's a couple of ways you can do it.
The simpler one would be to rule that whenever you roll one of your occupation skills on a routine task, and there are no particular adverse circumstances, you always achieve an ordinary success. This means the doctor can always vaccinate a willing patient, splint a leg in a quiet office, and so on. If they're trying to sedate a violent maniac, or stitch a wound on a storm-tossed ship, that's no longer routine.
The disadvantage of that approach is that the rubbish Doctor Beergut (Medicine & First Aid 10%) will always succeed at these, as will the amazing Doctor Lifesaver (Medicine & First Aid 90%). That might feel unsatisfying for both players - although the rest of the party will surely thank them.
A slightly fiddlier one would rule that whenever you roll one of your occupation skills on a routine task, and there are no particular adverse circumstances, you double your skill. Doctor Beergut will have a meagre 20% success rate with those vaccinations, Dr. Lifesaver will always succeed (depending how you want to treat botches) and Dr. Jobsworthy (50%) will also always succeed. This might be a good way to avoid any strange mechanics where it becomes sensible to take occupation skills and not spend points in them because you always roll them for routine activities.