As you develop a skincare routine, you may wonder how long to wait between applying products such as serums or sprays, sunscreen and cosmetics. The short answer is as long as you feel is necessary for products to layer properly. Dermatologists maintain that there are no firm rules for skin care application but there are helpful guidelines.SerumsSerums such as Matrixyl 3000 are formulated to absorb quickly. If you use too much product or apply another product or cosmetic too quickly, the combination may ball up or sting. If this occurs, wait several minutes between applying a serum and other products.Experimentation may be necessary to find out how to apply face products. If you are rushed in the morning, you may want to reserve certain treatments for evenings when you have more time and do not need to layer on sunscreen and cosmetics. This can be an ideal opportunity to promote absorption of pure hyaluronic acid serum with a dermaroller. Sprays Facial sprays are lightweight formulas that can be used quickly in the morning or during the day. A spray may be applied over or under makeup. If you are concerned that cosmetics may run or crease, experiment with the order in which you apply products.SunscreenSun protection is a vital part of any skin care routine. Even the gentlest protective products may sting when applied immediately after serums. This layer is absolutely necessary when using skin treatments that contain vitamin C or other ingredients that make skin more sensitive to ultraviolet rays. Try waiting several minutes between applying treatments and sunscreens.There are no absolute requirements about when to apply skin care products. Develop a routine based on the ingredients in the treatments you use. You may want to read product information or reviews for tips on how to combine serums with moisturizers or sun protection.