Upholstery questions.  

Leather is measured in square feet, not yards, and a full-size cowhide is usualy 50-60 square feet. But there will be a fair amount of waste unless you are doing a tufted style with separate squares sewn together (like on a Barcelona chair seat). 
Some cheaper leather is coated on top with color and maybe even clear coat for gloss.  Avoid this stuff.  It may start to flake or peel later.  Aniline dyed leather is a good choice.  
A beautiful fabric is a great alternative.  I would not go with vinyl, but I have an aversion to vinyl upholstery.  Lots of people like it, though.  

I'm normally in full agreement with spanky, but I've got a different view of specific vinyls; not for recliners but for most dining chairs. There is such a wide range of vinyl that it is tough to group it in only one category. I've found a couple of sources for good quality, thick, soft leather like black matte vinyl, which I thinks works beautifully for many dining chair seats. To me, it looks/feels better than some of the cheaper leathers, and it might actually be more expensive than some of those leathers. Some benefits of going in this direction are 1) easier cleaning, and 2) ability to exactly match the material if you are looking to increase your set size.
But for the OP's case of recliners, I would probably go with a good fabric upholstery for a redo job, as a good leather job will probably get very pricey.

8 yds (108 sq. ft.) per chair means you will likely need at least four hides for two chairs, which will very easily cost several thousand dollars, plus labor.
 
poor cows
 
 

cdsilva, I did a set of dining chairs in a really nice, soft, leather-like vinyl that was kind of on the high end price-wise.  And yes, it's a pretty good choice for dining chairs.  But it's still plastic and it's just my personal preference to use fabric or leather.  That's all.

I recovered an Eames Lounge 670 chair (in terrible shape) using leather salvaged from a hideous Italian sofa in excellent condition left in the alley at work for trash pick up.  It was vintage (and the color was not objectionable) so the sofa was actually covered using big pieces of leather (unlike the newer ones which uses smaller pieces stiched together).  I could never afford Spinneybeck leather, but I was able to salvage some good usable pieces from this sofa instead of letting it go to the landfill.
Vinyl is a good choice as long as it is a solid color and not pretending to be something else.  The only drawback is that it will never acquire the aging/distressing of real leather that is very desirable.