How many white shirts do I really need?

Two earns its place. One in a crisper cotton poplin for tailored outfits, one in a softer fabric (oxford, linen blend, or cotton-silk) for relaxed wear. Anything beyond that is preference.

Can I wear a white shirt if I'm not slim?

Yes, and the cut matters more than the size. Look for soft drape, a slightly relaxed body, and a longer hem. Wear it open over a fitted top, or tuck it into a high-rise trouser to define the waist.

What about an off-white or cream shirt?

Both work, and both can be more flattering than a true white against warmer skin tones. The rules are the same: fit, fabric, and the same twelve formulas all translate. If true white feels stark on you, try cream.

How do I stop the bust gape without going up a size?

Look for a cut with princess seams, darts, or a touch of stretch. If you love the shirt and the only issue is one button across the bust, a tailor can add a small hidden stay for under £10. Don't go up a size, because you'll fix the bust and ruin the shoulder.