Okay, so I have been looking for a bra that's not going to wear out in one month. I have a rather large chest (40DDD) and I have to buy all my bras at Lane Bryant, but everytime I buy a bra, it wears out and the straps and the elastic starts to lose its grip and the wire starts to dig in my ribs, so my boobs tend to just droop in these bras after a month. I hate this! And it's too expensive to be buying this every month. HELP, please!

Simple, stop shopping at Layne Bryant, and start shopping at a good lingerie store. I'm not talking about Victoria's Secret or Fredrick's of Hollywood that specialize in sexy, but real lingerie stores that cater to every woman's needs. Plus, you can get yourself measured for free to make sure you are wearing the proper size. A 40DDD in a cheap bra may actually be a 40DD in a good one.

You will spends a bit more for the bras, but they will last you upwards of a year, assuming you aren't doing anything to wear them out faster, like wearing the same bra for days on end without washing, not washing properly (hand wash or gentle cycle), putting the bra in the dryer, etc…

If you don't have a decent store near you, try figleaves, herroom, barenecessities, or any on line store that caters to all shapes and sizes. While you can still get your choice of color and style, try to stay away from the stores and sites that advertise "sexy" bras, which usually won't offer any long term support.
http://www.figleaves.com/us/home.asp
http://www.herroom.com/
http://www.barenecessities.com/

For a better quality bra, stay away from the thinner fabrics, like sheer, lace, or 100% cotton. The fabric itself won't hold up the weight of the breasts, so it only wears the bra out faster. A better choice are the ones with a trim or overlay to make the bra pretty, while still keeping the cup fabric sturdy and supportive.