In this case, I'm against it. Failure, that is.
This is not just a competence-porn issue, it's part of how things stay fun and interesting. This is not to say failure can't be interesting - it absolutely can - but it's rarely interesting all by itself. Failure is interesting because of the complications it introduces into the situation, and I'm all for skipping the middleman and jumping right to the complications. That is to say, if the dice come up short of the target, then it becomes a choice - would the player prefer to fail, or would he like to succeed with some complication or consequence offered by the GM.
This is easy to apply to basic difficulties (4), but how does it apply to higher levels of difficulty. Can a character take on enough consequences to successfully perform brain surgery?
Obviously, that's pretty nonsensical, so the rule of thumb is that consequences can improve the outcome by a single step, and only if there's a reasonable narrative for it (the player can male proposals if he likes). Depending on the scope of the activity, the task might be resolved in some way other than the initial skill rolled if that makes sense to the consequence. For example, if you need a computer program(7) but only roll a 5, then you might get a success by:
- Having someone else do it, in return for incurring a substantial (and immediate) debt to them. The program might even be held hostage for you holding up your end.
- You spend all night copy and pasting scripts from websites and you get you program, but your computer is now totally compromised by the various viruses to downloaded in the process.
None of that would help if your goal had been to design a circuit board(13), because that's a 2 step jump.
Having decided when and how failure happens, it's important to also talk a little bit about what failure means. Specifically, some thought needs to go into how re-trying works, and what the impact of failure is. In situations where the situation provides clear context for failure then that's easy, but the situation is not always clear. Looking at the circuit board example, that seems like a task with a very soft failure scenario. If you don't successfully design the circuit board, then why not just try again?
My thought is that if the task is one where the character can keep rolling til it works, then you're not rolling to see if ti works, you're just rolling to see how long it's going to take. That's reasonable, but only if time matters in the context of the game, which it often does not. But if everyone's cool with that being the case, then no problem.
However, some rolls don't invite that. There are situation where you want failure to stick, in which case failure is a demand for following a different course of action, mechanically handled by trying a different skill or by changing (perhaps improving) the situation enough to merit a re-roll.
With that in mind, the trick will be to communicate clearly to players whether they're facing a soft or hard failure. In the case of a soft failure, success is inevitable, and the roll is a shorthand for how many rolls its going to take (see the note on duration, above). In the case of a hard failure, there will be consequences of failure, and either the effort cannot be simply re-retried (or if it can, consequences stack).
So, with that in mind we know how to roll, how to judge difficulty and how to handle failure. That covers the basics. Now it's time to put some spin on it.