No scientific proof at all but it feels like washing powder does a much better job at removing stains than washing liquid.
It also seems more and more difficult to find washing powder in store as manufacturers are moving to liquid and even more a rip off - pods. Don’t get me started on these money spinners.
What is your experience and what works best?
I read the manual for my washer and have followed that. It “prefers” liquid but can take powder. That being said, I have a few items of clothing that explicitly say powdered detergent only (water repellent material). I’ve found overall that the less liquid detergent I put in, the better it cleans stuff.
Every 20 cycles (my machine tells me) or 1 month, throw in a cleaning powder with either the clean cycle or a heavy hot wash. It’ll help keep it fresh. Also keep the door open when you’re not using the washer to air it out, same reason.