I have 2008 honda civic lx, brought 2 years ago.

Recently, I began to notice that it is becoming more difficult to apply the brake to bring the car to a full-stop. and there is some screeching sounds sometimes when I put my foot on the break pad.

Are these signs that I should bring the car into a repair shop and possibly have the brake pad replaced ?

Normally, how long do people wait before replacing the brake pad if the car is driven mostly with city mileage?

does the general new civic warranty cover for such kind of brake repairing works at the dealer repair shop?

 

If you don't know how to work on a car and feeling the brake is weak, I strongly recommend to bring the car to a shop, NOW. Before you kill or injure some one else.

If you are going to do it only to yourself, by all means, go ahead.

Generic warranty would not cover consumable parts such as brake pads,,,,most likely.

 

It does sound like the brakes are worn out. The time or mileage to do that is impossible to predict since traffic conditions and driving styles vary widely.

Brake pads and rotors are considered "wear items"-- they wear out during normal use and are expected to need replacing several times during the life of the car. As they are wear items, the warranty does not cover them. (Other examples of wear items include the battery, tires, clutch on a manual, light bulbs, and windshield wiper blades). Any competent third party shop can do brake replacement, usually at a much lower cost than the dealer.

If you know how to take the wheels off (like for changing a tire) you can inspect the brake pads yourself.

 

Considering the type of question from OP, I don't think OP can make proper "road worthiness decision" even OP could remove tires. OP should do so with supervision from some one who has good knowledge about cars.

Better safe than sorry.