Yes. Using a mechanics inspection mirror and small flashlight, the pads may be viewed from underneath the vehicle, perhaps from outside if there are large holes in the rim. You should be able to see the wear indicator, a small metal arm that will begin to rub the rotor when the pad material is worn away. This "arm" scrapes the rotor constantly, making a chirp at first, then a scraping noise, which is heard first when coasting or with open windows. Continued driving insures you the cost of new rotors too.
Not sure, but I think the minimum thickness is 3/32".
2000 Winnebago Ultimate Freedom USQ40JD
, ISC 8.3 Cummins 350, Spartan MM Chassis. USA 1SG, retired;PPA,Good Sam Life member."We the people are the rightful masters of both the Congress and the Courts - not to overthrow the Constitution but to overthrow men who pervert theConstitution. "Abraham Lincoln"