This is a new thread designed to centralize my response to a bunch of stuff about crafting that's come up in other threads. You guys type way too fast for me to try and get to you all individually.
Regarding Always-On EffectsSo, here's the deal: when you're talking about what you can and can't make an "always on" effect, some interpretive dirty work is required. You have to look at what the nature of the effect is, how it manifests in play, and then ask yourself what makes natural sense. (Note: That means there might be differing answers. I'm okay with that.)
So, let's look at blocks and Armor. The rules say that an evocation block is something you manifest and can pay for duration on, but once it's bypassed, it vanishes. That presents an immediate issue for a persistent enchanted item, because once you defeat the block, what happens? Does it go away permanently? Does it get turned back on again later? Where does the power come from to reconstitute the block?
So, probably, an "always on" block is not possible. The nature of the action contradicts the idea of persistence. Hence, Armor.
Now let's talk about attacks. How do you have an "always on" attack? That wouldn't be like a gun, it'd be like a gun
that never stopped shooting. Evocation attacks require a process of gathering power and then releasing it. There's no "perpetual motion machine" for magical energy, just like there's no real way to make a gun with unlimited ammo. (Even though we shunt mundane firearm ammo off into a matter of narrative color, the analogy still works.)
So, if it's me, no persistent blocks, no "always on" attack items.
(I know, I know. What about the Warden Swords? Here's the deal: the Warden Sword doesn't expend energy to attack. Its damage comes from the fact that it's a sword. So it's a sword that has persistent spell effects on it, allowing it to ignore other enchantments. Even the counterspell ability,
you have to be casting a counterspell to get it to work, because the sword expends no energy. Make sense?)
About RequirementsYou don't have to have Crafting spec to craft. You just have to have slots. Crafting spec just lets you do it better.
About Armor and StackingSo, the rules say that Armor ratings are based on what the armor is ideally supposed to be protecting the wearer from. There's an implication there that the ratings could be situationally variable under different circumstances. So if we're talking about a big honking Kevlar vest that's Armor:2, we're also saying that it's designed to protect against bullet impacts. A quick Google search reveals that Kevlar isn't so good against the stabbity stuff. I'd also argue it isn't going to do a damn thing against an evocation attack.
So, a lot of times, there isn't any stacking simply because the way you're defining the protection in the fiction suggests that situationally, stacking wouldn't occur. So there's that. How you want to deal with stuff like Michael's mail/Kevlar combo armor or whatever is up to you. I'd have it as side-by-side bonuses (Armor:2 vs. X and Y). Whatever. It's all good. (I'd also have that add to the difficulty of Resources/Contacts rolls to acquire any.)
Armor and Stacking Continued: The Numbers and StuffIn Fate, a difference of one shift (or one step on the ladder) is bigger than you probably think. It can mean the difference between just taking stress and taking a consequence. It can be the difference between being able to take a consequence and being taken out. It can mean the difference between succeeding and needing to invoke an aspect to succeed. These thin lines manifest in actual play all the time.
So, you have to understand, stacking one armor benefit on top of another has a much bigger impact than it might seem from the numbers. Moving from Armor:2 to Armor:3 is a big step in weight class.
Let me do a quick example. Let's say you have Armor:2, and my Weapon and skill are such that I can inflict stress on you if I roll at least a 0 on the dice.
Without the influence of aspects, I have a 61.7% chance of doing that.
Now you upgrade to Armor:3. That means that now I need to roll at least a +1 on the dice to damage you.
Without the influence of aspects, I have a
38.3% chance of doing that.
That is a huge jump, which has a big cascade of effects on how things turn out. There's a 23% greater chance I'm going to have to spend a fate point to affect you now, every time I roll against you. And we're assuming your defense total stays the same here for simplicity - but in real play, it doesn't, because you roll every round and spend fate points of your own, further exacerbating the effects of this simple probability gap.
So, when I tell you that
any stacking changes things significantly, I'm not exaggerating.
Armor and Stacking Continued: System IntentFate is not a physics simulator. It functions poorly in that regard. That's just a simple fact about it. It relies on abstraction. So you make trade-offs when you're talking about situations like this.
On the one hand, we don't have stacking rules by default. The default assumption is the same as for blocks - you get the benefit of the highest applicable rating to your situation. On the other hand, we also don't have rules for armor ablation over time, which is a very real issue that faces real-life body armor manufacturers.
If I'm going to go out of my way to say that you can layer different types of protection for cumulative effect, then I'm also going to want to know when one of the contributors to the stacking has been damaged enough that they're no longer actually contributing. You don't get to be specific about the one and handwave the other - that would privilege the defender way too much.
(I know, I know... but what about Weapon ratings stacking? There seems to be no restrictions on that! Doesn't that privilege the attacker? Absolutely, yes, it does. The Dresden Files is gritty. Fighting is scary and nasty. You're going to get hurt. It's not an action movie, even when you have powers. So there's that.)
The problem from a design perspective is, if you open up one of those cans of worms, you have to accept the fact that if you're going to be fair about it, you have to open the others associated with it. That road has led, through the process of this game's development, to a whole lot of stuff I consider not fun. I chose to spare you folks that pain.
The Post-Soapbox SolutionThat said, if you really must, you could try this: vary it off of the "complementing a skill" rules on YS page 213-214. So, if you have two sets of protection at different totals that would apply together against the same source of damage (oh fine, like ensorcelled Kevlar), you can add +1 to the highest rating. But only +1, for the love of everything holy. So two Armor:2 values stacked give you Armor:3, not Armor:4.