Your brakes are the single most important safety system on your vehicle, and most failures give you warning signs weeks before they become dangerous.
A high-pitched squeal usually means your pad wear indicators are doing their job — time to book a service before it turns into grinding metal-on-metal contact, which means you're now paying for rotors too.
A soft or spongy pedal often points to air in the brake lines or a fluid leak. Don't wait on this one — have it looked at within a few days.
Pulling to one side under braking can mean a stuck caliper or uneven pad wear. It's not always an emergency, but it should get checked at your next visit.
If your dashboard brake warning light comes on, that's the car telling you directly — get it inspected as soon as you reasonably can.