Fortunately, the brake calipers have opening which allow visually inspecting remaining pad thickness by just removing the tires. I think your car has caliper's of that design.
When is the last time brake fluid was changed?
Without inspecting the brake system no one can tell you over the internet what definately needs to be done, and just replacing parts to try to fix a problem is unprofessional.
Normally as brakes get to the end of their life, anti-rattle hardware if installed have tabs which act as audible sensors for when the pads are low.
Since brakes are so important some things to consider, brake fluid should be flushed out and changed every two years. Using a turkey baster you can withdrawl brake fluid from the resorvior and refill with fresh correct fluid. Not as thorough as a complete fluid change, it is a start or a nice maintenance service to do every six months or so. Make sure no brake fluid drips on the car finish.
Brake lines should be inspected for leaks and condition while up on a lift.
Even worn shocks or collapsed springs can alter braking efficency, when the brakes are applied the car weight shifts to the front pressing the front of the car and the tires into the pavement, a very badly sagging rear end can prevent the weight shift from working.
My advice, if you have a professional do a pressure bleed of the brake system to change fluid, watch to make sure the work is done and fluid is extracted at all four corners of your car.
A check to see that the calipers are working and pad life is safe, is a worthwhile investment.
Make sure you have something like a quarter inch or more of tread depth aross your tire.
Only patronize dependable trust-worthy repair facilities.