Preventive Medicine: Last night, when I found it necessary to Google "how to unclog sink" I came across this advice:

Once every three months, fill every sink and tub in the house with water. With the help of friends or family members, simultaneously pull all of the drain stoppers up and flush all toilets in the house. This large volume of water will help flush out the larger-sized drain stacks and underground building drains.

A house high colonic.