Taken from Yahoo! Answers:

"take your wheel off. look at the brake pad- it sits against the shiny disc (called a rotor) and under the big metal thing (called a caliper. if you look at it long enough you will see the thin piece of metal separated from the caliper. there is a small metal tab that SHOULD come straight out and then turn at a 90 degree angle towards the rotor.

measure from the end of the tab and the rotor. anything less than 2 mm you should have gotten new pads already. in most cases, the "feeler tab" damages the rotor when it makes contact, but it sticks forward so that people will know when to change their brakes.

the light shutter that you are getting could be any number of things ranging from normal ABS operation, to your struts, to the rotors being slightly warped (also a normal thing with today's cars). all vehicles have a set of standards that they consider acceptable and all vehicles are different. it is cheaper (most of the time) to re-lathe your rotors, however after it has been done two or three times, that can't be done either. and replacement is necessary. the rotor having an un-even wear pattern going from the inside to the outside is also normal with todays pads."

 

I gotcha.

 

My brakes are also messed... I think its the type of pads Im buying cause they only lasted about 10,000 miles.

 

Ouch... I've had my car for 12,000 miles in 2 years so far and they feel pretty much the same... My brother used to have an Expedition and I used to really have to put my foot through the floor to stop the bus *ahem* truck. It's so different than driving a Mustang, but I love my car lol... little off-topic I know...