Jimm 8/23/2011The best test for when to replace the disc brake pads and brake shoes (friction material) is to remove the wheels to inspect the brakes. The friction material should not be worn away; causing metal-to-metal contact - in fact the brake material may be down to about 1/8" or 1/4" thickness. This would be time to replace the brake pads and / or brake shoes with new. Try the 'How-To-Guides' feature this website - for specific steps to inspect the brakes - including photos.
The best brake pads and rotors are the ones that; fit your vehicle, come with a lifetime warranty, install without problem, are quiet when in use, and last as they are supposed to - with no premature wear.
Personally, I tend to purchase the known and proven brand names for all brake products; Bendix, Raybestos, Wagner, Akebono, AC Delco, - they have known quality and are equal or better than original OEM in most cases. With lives at stake - I'll try not to cut corners in this area - to save a few dollars.