Is annealing 7mm STW brass worth it (round 2)?

[gamehawker]

Lets try this again. My first thread went off on a tangent by another member and I really did get any feedback.

I've got over 500 pieces of Remington 7mm STW brass last year and been reloading it for my two 7mm STW Senderos. I've been only using 200 pieces of it (saving the other 300 hundred until the current 200 is worn out) and have been getting good groupings after I have reloaded it three times.

I've heard that 7mm STW brass is usually only good to last for about 5 reloads.

I've also heard that you annealing brass after about after 5 reloads too.

I am thinking about getting in on the Group Buy on the Benchsource Annealing Machine:

http://www.longrangehunting.com/forums/f41/benchsource-annealing-machine-special-3-a-112784/

Would it be worth it to me to purchase a Benchsource Annealing Machine for my 7mm STW brass or a waste of money because the 7mm STW brass has a not so great case life expectancy?

I also have over 100 Winchester 7mm STW nickel plated brass from my Dad. Do you benefit from annealing nickel plated brass?

Thanks!