When I was a kid I learned to do laundry in an emergency. My Mom was incapacitated and I had to step up so my family had clean underwear. I had zero training at that time, and just dumped it in the machine and washed everything on warm. I don’t know if My Mom sorted, ironed, etc before that but we quickly became a low maintanance laundry family as I think I ruined everything that needed special handling and never used the iron. Everything I have learned since then has been from observing others when I happen to be visiting their home, or by chance observation on my own. So, in my experience…
Holes that “appear” in laundry for unknown reason can be from too much bleach. I am not ashamed to say I didn’t learn how to properly use bleach until I was 40 years old. Stretching knit fabrics too much can also cause holes.
Sorting and using hot water and a small amount of bleach (1/4c to 1/3c) can keep whites white. Once they go dingy I havent found a way get them back all the way. Not sorting is the fastest way to dingy. Or laundry detergent that doesn’t rinse completely. Borax can also help get/keep whites white. Baking soda can also help. But one additive at a time, not all at once. 😉
The best way to remove stubborn odors and some stains from laundry? Hang it on the line in the sun for a day or two.