As an identical twin, with identical twins, I feel I’m sufficiently qualified to weigh in here, and I’m of the opinion that twins should not be dressed the same.
From the perspective of being an identical twin, I’m glad my parents insisted we were treated as two separate individuals growing up - no matchy matchy names, no matchy matchy outfits. My sister and I grew up understanding that whilst we definitely had very similar interests (and faces!) growing up, and it was great always having a friend to play with, we were each our own person which meant we didn’t always have to approach the world as a pair and be reliant on each other to thrive. Our Mum jokes she did too good a job at ensuring we were independent after my sister worked and travelled abroad for several years!
As a parent of twins, it’s up to me to ensure my daughters have the same strong sense of self, and part of that comes from ensuring others see and treat them as individuals as well. Dressing them differently goes a way to helping with this.
I hear other twin parents on this thread saying it makes their life easier to dress them the same, but to be honest I would rather my life were a little harder (though I can’t say this is my experience) if it meant people weren’t constantly muddling them up, or treating them as the same person, as they hate people calling them the wrong name and will correct them every time.
@LePetitMaman I don’t know where you got the idea that “you will see literally every twin parent telling you, it's the twins themselves that refuse to be different, up to a certain age”, or 95% of the twin Mums on this thread are of the same mindset as you. My girls have never been bothered about dressing the same, the only time they went out in the same outfit is when they happened to both want to wear the same thing that day, and similarly to not forcing them to dress identically, I’m also not going to force them to dress differently to each other because of my own view on the subject.
They’re 10 years old now and certainly have their own individual sense of style.