Decide what goes underneath
Over a T-shirt, a cardigan needs enough room at the shoulder and upper arm to avoid dragging the sleeves. Over a shirt, look for space around the cuff as well. Put both layers on together and reach forward; a cardigan that fits alone may feel cramped over another garment.
If you want to wear it as a top, check the gaps between the buttons in a seated position. A light underlayer can add coverage, but it will not fix uncomfortable pulling across the front.
Change the fastening
Wearing the cardigan open reveals the layer below and creates a vertical line. Fastening it gives a more continuous front. Try leaving a lower button undone if the hem bunches at the waistband, provided the shape still feels comfortable and the opening is where you want it.
Do not force a particular button arrangement because it looked good on another cardigan. The position of the buttons and the stretch of the ribbing affect the result. A cropped style and a long, draped one need different treatment.
Give it a place in a real outfit
With a skirt, check whether the cardigan hem lands where the skirt widens. With trousers, see whether a bulky waistband shows through the knit. A smoother base layer can help without requiring a new cardigan.
Before leaving, put on your coat. Thick cardigan sleeves can bunch inside narrow coat sleeves. If that combination is uncomfortable, keep the cardigan for milder days or use a roomier outer layer. Store it according to its construction and care label when it is not in use.
