Do I have to match my pillow to my sheets and duvet cover?

I just got my first opportunity. I also need new sheets. Do I have to match my duvet cover and pillowcases (eg gray) or I must agree with my sheets and pillowcases? (For example, the white border with gray stripes) while obtaining the gray cover decorative pillows blanket is not used …. only two pillows to sleep

A pillow] to sleep in the form 2] "decorative" pillows [supported in sleep] coincides with the quilt

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