Determining whether your makeup palette has expired can be a bit tricky as there are no hard and fast rules. However, there are a few signs you can look for:

1. Change in Color: If the colors in your palette appear to have faded or changed, it could be a sign that the product has expired.

2. Change in Texture: The texture of the makeup should be consistent. If you notice that it has become hard, chalky, or is not applying as smoothly as it once did, it may be time to replace it.

3. Smell: A strong indicator of expired makeup is a change in smell. If your palette has a strange or unpleasant odor, it's likely expired.

4. Skin Irritation: If you notice any skin irritation, redness, or breakouts after using the palette, it could be a sign that it's expired.

5. Separation: In cream-based products, if you see any separation or oil forming on the surface, it's a sign the product has gone bad.

Remember, the shelf life of a makeup palette can vary depending on the type of product. Powder-based products like eyeshadows, blushes, and bronzers typically last longer, around 2 years. Cream-based products like cream blush or eyeshadow have a shorter lifespan, usually around 12-18 months.

To extend the life of your makeup palette, always store it in a cool, dry place away from direct sunlight. Also, always use clean brushes or applicators to avoid introducing bacteria into the product.