No matter how careful you are, your sinks are going to clog. Sinks accumulate hair, soap, and other foreign objects. Even though most modern sinks have strainers, their continual use causes them to stop and back up.
Most bathrooms and kitchens sinks are connected through a network of pipes, which means that an issue affecting one can affect them all. When your sink backs up or clogs, the clog source is usually further into the pipe system and not in the actual trap. When this happens, store- bought cleaning solvents are ineffective, and professional equipment is required.