Murph, congrats on your new shirt, belt and bottoms! A red belt is most useful, you'll see. There are tons of other color combinations to be made with it too.
To answer you question: it really depends because noramally, my small wallet forces me to buy piece by piece (the ones on sale preferably) in hope of finding unity afterwards. This method also leads me to many returns, and some mistakes. Sometimes, in a store I know and trust, I will buy 1,2,3 pieces that work together. This represents a splurge for my teacher's salary, these items usually not on sale, but it is a much durable, useful purchase: sleeves'length will match, hems will fall right where they should, fabrics will work one with another for minimal creasing, bulking, and then I can play around for shoes and scarves. It's like buying a look instead of just one piece. Later, when I am in a rush of just not in a mood for thinking up an outfit, I simply revert to the original things bought together and go from there.

it gives us a good idea of what to wear and what will look good on us.

I had actually never thought of doing this. I might start. My wardrobe is a mix but not a match at the moment.

I have never done this but I do love looking at how items are styled. For me it’s more the vibe of an outfit that inspires me, rather than the exact combination of items.

I shop pieces. Over a decade ago, I worked in a boutique that catered to middle aged & older women, and I would style the mannequins in a top from one label, jacket from another, pants from a 3rd label... and so on. The owner's daughter would come behind me on my off days and redo all my mannequins to wear the coordinating pieces from the same label and it used to peeve me off. It drove me bonkers, so I just quit doing mannequins & looked for a job in a store that allowed me to do my thing.

This is so interesting. It’s made me realize how little I pay attention to the full look on mannequins. I home in on individual pieces and imagine my own stylings pretty much only when I try them on. Maybe I need to pay closer attention!

Janet, your intuition and style is evident! You don’t need a mannequin’s help

Cute shirt! I definitely make note of the styling on the mannequin. I don't usually buy the entire look but it helps me pull an outfit together.

I have done this a few times. Once DH and I walked into a store and he pointed out an outfit that he thought would look good on me. I bought the pants, top and blazer. I loved those pieces. I could use them with my wardrobe in all kinds of combinations. He pointed out another outfit another time that I bought and I loved that one.

I don't do this now because I am retired and I have a much smaller wardrobe (and clothing budget).

Love the Boden shirt! The combo of red and olive sounds fab.

I don't often buy whole outfits based on the mannequin or model, but that is usually because of sizing issues (one item will fit but the rest will not work for my body shape, etc.). There have been many times that I have wanted to copy the model but could not. I think that putting together an outfit based on the mannequin or model is a great idea.