Originally Posted by theory
Basically, you're asking, what damages the car paint? We need to know cause and effect in order to make better decisions. Here's what damages car and car paint:
1. Sun - this bad boy causes fading. It also causes parts to expand due to heat, which knocks off the tolerances of parts as it contracts.
2. Washing. - this bad boy instills scratches. The smallest speck of debri caught in a microfiber towel is more than enough to leave visible marring.
3. Water. - this bad boy is the most powerful solvent in the world. Its slowly dissolving all the screws and damaging electronics.
4. Freeze Thaw cycles - this causes parts to contract, knocking off tolerances.
In the case of soap, washing will instill scratches, no matter how careful you are. The more you wash, the more scratches you instill, the duller the car becomes. A clear wrap is the only way to prevent scratches.
So is car soap good enough? Yes.
My car has scratches. I do a mediocre job with touch-up paint. It's covered in bugs and pollen from May-September. I was just curious if the cheap soap was infinitely worse than the stuff that's 5 times more expensive. I want to keep my car nice, but I get groceries in it and drive down gravel roads.