So, since it comes up all the time I figured it was time to get a blog together. I don't know why I'm the one doing this, analyzing things is OTHER people's job, not mine. XD Anyway, this will be about ability level boosting/skilling up your cards. It's not an easy topic, despite all the data that exists for review the methods employed to improve your cards are individually preferable and there's not much to discredit or prove why those methods are good or bad. Whatever works. I look at the best/most efficient method, as that which guarantees a level. It may seem to cost more because of the work and time involved in getting those higher percentages, but it should even out if not come under the same point as dozens of failed attempts with less money spent on the cards to fail with.
So, lets start with UR+ cards since there's probably at least a couple that people would bother with, right? Now, thanks to lopezandym's post on neoseeker we have something that's close to fully accurate on percentages to use as a guide on what exactly you'll need to get those best odds. I'm going to say now though, that after a certain skill level, things get ridiculously difficult for anybody, but especially a non-paying person, and this is even more true if you're working on Legendary cards, which I was going to cover in another blog, but this is already discouraging enough so I might not bother lol.
So, you've got that AP Cap all nice and fused, and you want to get that bad boy up to speed for your defense deck, or whatever. So, here's what you'd have to do for the absolute best odds of getting a skill level, and getting up to 10, without using an ability boom. Make no mistake, this process is long, and expensive if you want guarantees, and aren't comfortable banking on luck.
You'll need to have a good bank of R+ cards farmed from BOTH mission 2-4 and 2-3. The reason you will need both is because you'll have to use either the Iron Man cards to skill up the Wolverine cards (or vice-versa) to skill 4. You can use 10 UC cards to get whichever R+ cards you're boosting up to skill 2 to start. Using 10 basic fused rares will get those boosters to skill 3. To get to skill 4 you could still just use R+ cards, but even with 10, you'll only get about a 75% chance. Still, when boosting a booster, I think that's acceptable.
So, you've got your 10 R+ cards up to skill 4. Now you have a 100% chance that they will give a UR+ card an ability level...up to 2. To get a UR+ up to skill 3 however, you'd need to have those boosted boosters up to skill 5 just for an 80% chance of level up. Or you can get 9 cards at skill 7, and 1 at skill 2 for 100% chance. These figures are based still on R+ cards being used on your UR+ at skill 2. At skill 3, the UR+ would require 10 skill 9 R+ cards to get 100% chance of ability up. At skill 4, you can't use R+ cards at all to get a 100% guarantee. So you can theoretically use R+ cards up to skill 4 with a guarantee you'll get that ability up, but here's the problem:
The process by which you'd have to get those R+ cards up to such high skills would require an insane amount of farming, and card space because you'll be boosting boosters of boosters just to boost your boosted boosters. If that sentence sounds horrible, it's because that's what you're stuck with unless you make the jump to SR+ cards. And even then the process is pretty much the same, not to mention you will only get up to skill level 6 on your UR+ card with guarantees, but still using the same grueling method as earlier. Only using SSR+ cards can get you all the way to skill 10 with 100% guarantees the whole time, and they would still require boosted boosters for those guarantees. Even using Legendary cards (because they're just sitting around) would require you to have them at skill 4 to get a UR+ to skill 10 guaranteed...and we're still talking having several DOZENS of Legenadary cards to do so with.