Yesterday I'd picked up some new pair of gloves and wanted to give it 4 linked sockets so I could use it for a skill combination of some kind. (I think I wanted to link reduced mana to a bunch of auras.) I ended up using 15 fusing orbs to get my links. Then I went to my new crafting buddy Vorici and asked him what he'd charge to 4-link an item. 5 fusers. That sure would have been a better choice than the 15 I spent, but maybe I was just really unlucky? I thought I knew the rough odds of each link result so I decided I wanted to work out the math and see if I should use Vorici next time I want a 4 link or not.
I decided to double check that I actually knew the math and discovered that not only did I not know the real odds, it seems like no one does. I found some discussions about the odds of making a 6 link and one of the head developers has posted that the odds of getting a 6 link are a little better than 1 in 1500 and using the 20% quality trick will more than double your chances. So you should expect to spend a little under 1500 fusers to get a 6 link or if you're willing to use a ton of armourer scraps you can probably get there in more like 600 or 700.
Vorici's charge for a 6 link? 1500 fusers.
I found another thread where people talked about the math behind Vorici's socket recipes (the jeweler odds are known) and he charges a pretty significant premium for his socket recipes. But his link recipe seems to be only a little pricier than the actual odds. And while you could probably fuse cheaper with a lot of scraps that also comes with the extra cost of time. Clicking 21*700 times is a lot more than clicking 1450 times, especially since with straight fusers you can spam shift click while you need to spend a lot of extra clicks changing between scraps and fusers with the quality recipe. And clicking 1450 times is still a lot more than clicking once for Vorici to do his dirty work.
Nevermind the fact that 1% of people who try to make a 6 link will end up spending at least 10000 fusers to get there!
It sounds like most of the time it'll be cheaper to do it the hard way but Vorici is not charging much of a premium to fuse and he saves you a lot of time. Time you could spend having fun playing the game or farming the extra fusers and he comes with an actual concrete goal. 1500 fusers is a guarantee. You won't get unlucky and need tens or hundreds of thousands of fusers. You also won't get lucky and need 5.
People seemed to be claiming that his socket cost premium scaled with number added. If you assume the same mechanic behind his fuser premium then the same sort of logic should apply to all of his fuser recipes.
I think I'm willing to pay that premium on the link recipes. You're probably looking at spending 4.5 fusers on average to get your 4 link so paying Vorici his 5 is just safer and faster. It's certainly my intention to use him going forward for all my fusing needs. He's not high enough level for me to use his 6 link recipe but then again I have 36 fusers in my bank, not 1500, so I have plenty of time to level him up.