That's not always the case, some of us do check our brakes. Matter of fact I had my (reliable) mechanic tune up my car and even check my brakes last week. Two days ago I crashed due to BRAKE FAILURE!!! This was WITHOUT warning and should NEVER happen. I am thankful I came out with only a few scratches. It was severe enough that my car was totaled and the air bags deployed. I still loved my car, but there is evidently something wrong and Nissan should take responsibility before someone is killed, not only in the Nissan, but in the car you may hit as a result to brake failure.
I have a 03 altima and from all of these comments maybe some of these mechanics should not be touching cars. If you have brake problems and they have just checked your brakes you should not have a problems. Brakes are your number thing on your car except the blood of your car which is oil. If it was me I would actually take the time and learn the basics of my car like maintenance it. Now if your brake pad is metal to metal it does make a noise if people say it doesn't they have no clue whats going on. I have only replace my brakes once and that was 60k which is normal from the factory. If your have heating issues check your blower motor or the resistor check the thermosat or even there is air trapped in the system that needs to come out its called bleeding it. The water thing sounds like you might have a leak somewhere in your ac system which is possible. They have ac dye which is made to find leaks. Now if your burning oil I would suggest
using a thicker oil, you a oil stabilizer which Lucas makes or even see if the oil sending unit is working properly.
I have had my 2003 Altima 2.5 since new and I have had no problems at all. I do the oil changes every 3 months and I use a synthetic oil, I change the air filter as required and rotate the tires, and I use my gears to control speeds when coming down a steep hill, this saves the brakes. I would buy another Altima 2.5 without any hesitation.