I'm pretty sure fashion rules for girls' jeans are totally different. AKA I routinely break your rules #3 and #4. The jeans I'm wearing right now, actually, in fact. I won't wear acid wash/supremely light, but I personally think it's important to have a variety of washes, from ultra-dark to mid-grade. Button-up flies are like intermediate level. I do love the 'Lucky You.' It takes some bravery to wear button up flies. But if you learn to do it right you can pull it apart with a tug at the right angle. It's really just doing them up that's a hassle at that point. I wash my jeans when I look at them and know they need to be washed. IE, if there are visible stains, wash them. If there aren't, don't. (If they are covered with cat hair, it's not a stain but it's annoying, so I will cave sometimes.)
I'm exclusively talking about men's jeans and men's fashion, e.g. 3 and 4 are subjective design/style topics. I also wash my jeabs when theyre actually visibly dirty, normally thatll be like once a week or two if i wear them very frequently.