1995 C280 Brakes! Help!

[David C Klasse]

I thought I heard metal on metal at 77k miles. So I took my car to the mechanic to have him check out my brakes, he said that I still had 50% left on them. So I felt rather stupid. Anyway, the car was purchased used at 71,000 miles, and I have NO maintenance records, in which the Kia dealership (believe it or not) said they would provide for me (I still have to get back to them). Anyway, I don't know when the brakes were last replaced, or if it was serviced at a MB dealership (rather if new brake pad wear sensors were put on).
Well I'm not hearing metal on metal (so I think?) every time I am in a parking structure or am braking close to a wall. No brake lining lights have lit up. Before I make a fool of myself again having my mechanic check it out AGAIN, and have them still be good, are there any other relatively easy way to check the brakes without taking it in? Thanks so much for all the help.