TL;DR Summary: days to wait for a decent epic of the type you want is roughly 200 divided by the count on AH of that epic right now. VERY gross quickie calc best thought of as a hint of the duration (weeks or months or years) rather than an actual count. How I came about it is below.
Here are some statistical calcs on epic cash-box weapons broken down into useful tidbits. You can check here for the underlying math: expected trials from a set to achieve a given chance of at least one success. Calcs assume epics are a 1:50 drop from a cash shop box. This matches the average I got opening 102 boxes. It’s not exact, but for the sake of the math, let’s run with it and see where we end up.
Lets say you want an epic from a box. How much would it cost using either cash shop keys (money) or patron keys (time) to achieve a particular chance of success? First is for any epic, then only “good” suffixes (not ward or recovery), and then an exact suffix.
- 25% $00162.50 / 00.36 years | $00227.50 / 00.50 years | $01133.75 / 02.48 years
- 50% $00390.00 / 00.85 years | $00546.25 / 01.20 years | $02730.00 / 05.98 years
- 75% $00780.00 / 01.71 years | $01091.25 / 02.39 years | $05458.75 / 11.96 years
- 95% $01683.75 / 03.69 years | $02357.50 / 05.17 years | $11795.00 / 25.85 years
The above isn’t as interesting as the implications from the number of openings required to achieve a given confidence level for success (any, “good”, and exact).
- 75% 0624 0873 04367
- 95% 1347 1886 09436
- 99% 2071 2899 14504
These numbers help determine how long you might have to wait for your desired weapon to show up on the AH. I’m guessing the number of epics on AH of a given type represents an average result of the past 5 days of openings. You never get one you can use and you’re greedy and you’re realistic; ie. you get one, try to sell it, fail, reprice, it sells.
Simplifying that even more, you can get days until you see what you want by dividing the number of openings you feel good about by 10x Epics you see on the AH right now of your type.
Want an Anima weapon of non-bad suffix and there are 2 Anima on AH right now? You’ve got about 90 days until you’re 95% sure to see one you want. Want a particular suffix? Expect to wait a year.
NB! There’s a lot of over-simplification and guessing going on in the AH-days calc, but it should be good enough to give you a feeling of the scale of the wait in very general terms – weeks, months, years, … centuries.