96dcmss is right "IF" your pads have only 2.5mm left they need to be changed.
That possibility just seems far fetched to me. My original pads on my 04 went over 70K before I changed them. They could have gone longer since they had about 25% of the pad left.
There are members on the org that have gotten over 100k on their original pads. Other members like Koz change their pads every 20k because they are hard on the brakes or just perfer to know they always have a great set of brakes.
I would recommend using nothing but OEM pads even if you do it yourself. $48.76 for OEM front pads. See link below.
http://www.trademotion.com/partlocat...05&catalogid=1
Take one of your front wheels off snap a pic like icantsee and let us take a look.
Also you did not mention what year and trim line 4Runner you have. This is important since the SE models have a 13.3 inch front rotor and take different pads than the SR5 & Limited which have a 12.6 front rotor.