As I look around the internet lately I've seen the same question asked multiple times. What should I buy first with my Emblems of Frost? It's not a surprising question, but I have been surprised by consistency of the answer and by the confidence with which it is given. Almost every time I've seen this question answered, the poster says to not buy anything else until you've completed your tier set.
The logic seems to be that, because our Tier set is so well itemized and the idol is a smaller upgrade that we can make due with the Idol of Lunar Fury for a few weeks while we pick up the emblems for our Tier set. This isn't bad logic, but I do disagree with it. In this post I hope to show you why you should considering picking up the idol as your first Frost Emblem purchase.
Time Value of Gear:
Most of my education has focused on Economics and Finance, and this situation seems to be similar to a financial concept called the time value of money. In short, the Time Value of Money shows that the present value of a future payment is relative to when will receive that payment (in financial terms it also depends on other things like interest rates). Assuming that the interest rates are the same and the payments are the same, the payment you receive first has a higher value then the payments you receive after that.
Granted in the real world the payments and interest rate will not be constant. It is quite possible for a future payment to be worth more in terms of present value then a payment made today, but hopefully you see my point. A smaller payment received now may be worth more then a future payment given the right terms and interest rate. I know this doesn't necessarily translate smoothly to gear in a video game, but I think you can see how gear received today can be worth more then gear received at a future date.
So the question is which will help our DPS more? Do we take the idol now and delay when we pick up a few of the tier pieces or do we pick up the tier pieces as soon as we can and wait on the Idol?
A Question of Timing:
I'm going to hold off on looking at it from a DPS point. The numbers will vary depending on the stats you star with, but I will stipulate that a single piece of Tier gear is probably a larger DPS increase then upgrading the idol. However, I do want to look at it from a perspective of timing.
I want to make a few of assumptions. First, lets assume we pick up the maximum number of Frost Emblems each week. Second I will assume that we pick up the two cheapest pieces first and then the 3 more expensive pieces. Third, I assume that you are picking up pieces as soon as you can even if it doesn't provide a set bonus. Fourth, we know that the first gate won't open for 4 weeks, but I will assume that the other gates will open after just 2 weeks.
The shoulder and glove pieces each cost 60 emblems. The head, chest, and legs each cost 95 emblems. The idol costs 30 emblems. To pick up 4 tier items and an idol, you need a total of 340 emblems of frost. To pick up just the Tier set you will need 310 emblems. So, how quickly can you get to 310 and 340 emblems.
You can pick up 6 emblems the first time you run the new ICC five man instances. If you run the random every day you can pick up another 14, and there are 5 emblems available from the weekly quest. From ICC you can pick up 2 emblems per boss on both 10 man and 25 man. During these first 4 weeks that means you can pick up 16 emblems from ICC per week. If you add all that up you see that you can get a total of 35 emblems per week for the first four weeks plus 6 additional one time only emblems. That is a total of emblems 146. When the first gate opens 3 new bosses will be released. With 7 bosses available you can get a total of 47 emblems per week. After 6 weeks it is possible to have a total of 240 emblems. when the second gate opens 2 additional bosses will be available. With this, the weekly max will increase 55 emblems per week. After 7 weeks you would have a total of 295 emblems. Not enough to complete the set. After the eight week a maximum of 350 would be available. With this you could complete the set and pick up the idol.
In short, it doesn't matter if you wait to pick up the idol or if you pick it up first. It will take you a minimum of 8 weeks to pick up four pieces of T10 gear. That is 8 weeks of missing a clear and irreplaceable DPS increase. I'm not saying picking up the idol first is a clear winner. Taking the idol first will delay the first for pieces by a week if you pick them ups ass soon as you have the badges available, but is that a huge DPS loss? I don't know. It's hard to argue if missing a smaller upgrade for 8+ weeks is a bigger deal then missing a 3 larger upgrades for one week each. However, the answer is not as clear cut to me as some people are suggesting.