Your FAP is more eco than armor unless you have to FAP while killing a regen mob. IMO, for people with 24+ heal per pec, unless in a timed event, the strategy should always be to wear only enough protection to not die during the encounter with one mob. Then you heal up and go again.
One of the advantages of that strategy is it usually lets you avoid double (over) protection if you use plates, which has become very easy to have happen and is not shown by the entropedia tools.
Use (L) armor with over 10k durability (most have that but a few crappy models don't). As has been mentioned it has at least 10-15% less decay than an equivalent UL armor.
1) Wear armor with about the same protection distribution as the mob's damage distribution if you are going to wear plates, and make sure the plates have the same distribution as well.
2) Alternatively, use plates with protection that are completely different than the armor but still a type of damage that the mob does. This is the OPTIMAL way of armoring since the last change if a mob does similar amounts of different types of damage that will guarantee you have no double (over) protection, but unfortunately the selection of armors and plates makes it almost impossible. For example there are only a couple of plates with significant cut or stab protection that don't have as much impact protection, and the same is true of armors. Polaris happens to be one of those. Strangely enough some of the dragon plates and the upper level firewall armors are the most innovative items for this strategy.
Let me explain why those two strategies are wise if possible for your mob.
Case 1. Let's say you get attacked by a mob that does 25% cut and 75% impact, for 60 points of damage. You are wearing armor that protects 15 impact and 12 cut, with plates that protect 12 impact and 9 cut (total protection=27+21=48). Your armor is presented with 25%*60=15 points cut and absorbs 12 points of it, and 75%*60=45 points impact and absorbs 15 points, and then decays according to 27 points protection (the higher the damage absorbed the higher the decay). Then, same 15 points cut is presented to your plates and they absorb 9 points of it, and 12 points of impact and decay according to 21 points protection. You take 15-12-9=0 cut damage and 45-15-12=18 impact damage.
So you reduced a 60 point hit to 18 points (42 points protection), while your armor decayed for 27 points and your plates for 21 points (which totals to 48 points protection). If you had been wearing armor with exactly the same ratios protection as the mob damage, you would have reduced the damage to 12 points while absorbing the same 48 points on your armor and plates. You can see that the greater your armor and plate protection ratios differ from the mob damage ratios, the more overprotection you can get while still failing to fully protect. Now note that splitting the damage between the armor and plates (and generating an overprotection of 6 points) most likely still protects you more efficiently than just wearing an armor that protects the full 42 points because the cost per point protection increases exponentially, but there's a point where you'd be better off not wearing plates and bulking up the armor.
Case 2. Same mob. Same attack. You are wearing magical, nonexistent plates that protect just 25 cut, and armor that protects only 40 impact. This time you are protected for the all the cut again and 40 impact, a total of 55 protection. You take 5 points of damage and have no overprotection.
The potential advantage of the second strategy becomes much greater when mobs hit for low damage (mob damage ranges from 50% to 100% max just like ours) and you are trying to protect for their max hit (or even a crit). Even with the smallest hit you have no overlap protection, whereas in strategy one you can.
But if you only need to wear enough armor to take off up to 50% of a max hit, and you have the same protection ratio as the mob's damage ratio, you can avoid ever having overprotection without needing to find nonexistent armor and plate options. Which brings me back to why i said that having an eco FAP and armoring just to survive the mob can provide a synergistic benefit to economy.
That was a long post but i wanted to explain to others who aren't really clear what the repercussions are of the armor changes what strategies are available now. It's become much easier to overprotect with plates, even while taking damage, so it's worth thinking about your setup.
Here's hoping MA or a PP uses the opportunity to introduce single-type armors and plates (like chelydra and chromatophore (rest in peace)).