You can determine your skin type by washing your face with a gentle cleanser, waiting about an hour without applying any products, and observing how your skin feels. If it feels tight or looks flaky, you likely have dry skin; if it appears shiny all over, you're probably oily; and if you notice shine in your T-zone but dryness elsewhere, combination skin is your match. Your skin type can change over time due to factors like age, climate, and hormones, so it's worth reassessing every now and then.