Except for Bl. Maria Taigi I can't think of any other saints who were married and subsequently dressed plainly and without adornment of any kind.
I've read about other saints that began doing so when their husband's died and they sold their jewels and clothing and often entered into convents.
I imagine there were plenty who were poor and so it wasn't a choice really to dress in clothes that were more colorful or made out of finer material.
St. Therese's mother made lace and is pictured wearing nice clothes, with her hair fixed and I believe she and her daughter's all had their ear's pierced. Her husband was a jeweler wasn't he? Aren't the Martin's close to being canonized?
Weren't most of the saints on record not married and not living "in the world" ?
I believe based on what I've read and learned that we have to live according to our state in life. Some saints in the early years of the Church were royalty. They had to dress according to that particular state .. finery, jewels... However, once the King or Queen died, many saints ultimately gave it all up and led a life of poverty and deprivation.
If we're married and have to earn our livings "in the world" we have the tough task of moderating our dress to reflect those states without compromising modesty whether in the form of being properly covered, or by not dress ostentatiously to attract attention or jealousy.