When to put Resistance in Extended Tasks? I understand Armor with Adversaries or Ships, but what is the Difference between a Task with 2 Resistance or having just a +1 Difficulty. Can someone maybe give me some examples?
IMO, Difficulty is for when the task is actually harder to accomplish. Resistance is, instead, things that make the task take longer, but can be overcome if you pay attention (remember, the Intense Scrutiny Talent lets you get through Resistance more easily, as do other Talents that have to do with paying careful attention to your work).
Anything best described as a distracting extraneous variable (ie: the people you're interrogating having secrets other than the one you're looking for, an ongoing but not dangerous power fluctuation in the system you're fixing, an interesting but unrelated anomaly in the astrometric data you're examining) could be a source of Resistance. Or just the decision that this is a task that may take a very long time without careful investment and attention.
Resistance and Difficulty are not always straightforward to distinguish in an Extended Task. I always compare it to normal attacks: The Difficulty means that it is harder to hit a target. Maybe the target is farther away or is very small. In the context of an Extended Task this could mean that a machine you are trying to repair has very small parts or is foreign to you.
Resistance negates damage. So even if you hit the target and roll damage, it is negated by Resistance. In the context of an Extended Task, I ask myself: Is there something that negates the work I put in? This could mean external factors that continually damage the machine further as you try to repair it. And of course the examples that Deadmanwalking already mentioned.
Oftentimes it is a file line if something increases Difficulty or Resistance. From a game mechanical point of view, increasing Resistance makes the ET longer and you won't get Breakthroughs quite as often. Also, just increasing the Difficulty can be frustrating if it goes to 4 or 5, especially if it is an ET where no-one else can realistically assist. In that case, I find it better to set the Difficulty to 2 or 3 and increase the Resistance instead.
Remember that Difficulty reduces with each Breakthrough, but while Resistance can be negated, it doesn't reduce in the same way, so it constantly applies. I'd guess you could create an Advantage that might reduce Resistance (in the same way that you could reduce combat Cover with an Advantage to get at the real target beyond, by methodically destroying it!).
Another explanation to add to the list is that the task itself is just fiddly - trying to repair a circuit through a small opening, or by remote control, for example. In the first case, you could create an Advantage to widen the opening, but this would be a Task in its own right, delaying the repairs.