The Flying Penguin wrote on Jan 17, 2023, 11:57:
Snipped for brevity, but good advice.

What I typically do is once a year take off the plumbing from the wall up to the bottom of the basin. I have a half-round brush that attaches to flexible shafts that then go in to my cordless drill. I run it through the pipe after dipping the brush head in hot water completely. Then with the drill on high and torque set to "I want you to drive a screw through granite", I run it back and forth through the pipe repeatedly until it is clean. Most plumbing under sinks are connected with ear flanges so they're easy to take apart by hand. This lets me know I have as clean an inner diameter as possible.

All of my basins have cross bracing where the plungers screw in to as they are of the tap to pop up and down kind. I'll run the brush head up from the bottom to those cross braces and then use a bottle brush from the top down once the plunger is removed. The plunger itself can be scrubbed with a bit of Simple Green and a fingernail brush. Then I just put it all back together. Never had a clogged or slow drain since I started doing that. I'll even do it in the kitchen, too, since you'll get food debris build up from simply doing dishes.

If you're on a septic system, never, ever use Dawn. It's a great way to get a thick "blanket" of off-white grease floating on top of your tank and those tablets/pouches you're supposed to flush down every month often end up with the granules just hitting that blanket and never making it to the bottom where they are supposed to go. Mrs. Meyers and Seventh Generation make products that are safe for septic systems but are all natural that don't create that "blanket".