There's no way to answer this, sorry. If you look up close enough, fashion has been changing on a regular basis for hundreds of years: sleeve styles, shoulder widths, waistline heights, and more varying every few years to allow some people to distinguish themselves as at the forefront of fashion. If you back up far enough, Western fashion hasn't changed since wrapped garments were exchanged for cut-and-sewn ones. Giving the modern men's suit either fifty years or 120 is arbitrary - we could also go back to the late seventeenth century, when Western men started wearing a suit made up of a coat, vest, and breeches, or we could could go back a few centuries to the switch from the gown to the short doublet. Typically, changes in fashion are slight enough that most people can't tell the clothes on either side of them apart very well, and it's only when comparing two garments/outfits/styles from a decade or more apart that they see a difference, but that doesn't mean that fashion only changed after a decade or more.