In the morning, the skin appears dull and dehydrated from trans-epidermal water loss that occurs overnight. It may feel tight, dry, and lack radiance due to decreased oil production during sleep. Pores can appear larger after being relaxed all night, and the skin may show signs of puffiness or undereye circles from fluid accumulation while lying down. In addition, your skin may exposed to UV rays, and free radicals during the day. 

Therefore, your AM routine should focus on:

1. Cleansing overnight oil and impurities using a gentle cleanser

2. Applying antioxidant serums to protect against environmental damage 

3. Moisturizing with a lightweight formula 

4. Using broad-spectrum sunscreen for UV protection 

At night, the skin looks tired and lackluster from a day's exposure to environmental stressors. It feels oily, congested or grimy from buildup of sebum, sweat, dirt, and makeup residue. Signs of redness, dryness or irritation may be more apparent from daytime damage. Pores can appear more clogged after being exposed to impurities all day.

Your PM routine should concentrate on:

1. Deep cleansing to remove makeup, dirt, and pollutants 

2. Applying nourishing and anti-aging treatments

3. Using richer, more emollient moisturizers and oils to hydrate intensively 

“Alright”, you say, “but that sounds like a lot of work.”

If you don't want to use so many products in your skincare routines, you can streamline them to just the essentials. This could be done by using versatile and powerful products that target multiple skin needs and concerns. This way you can simplify your routine without compromising the results.

It is important to have separate AM and PM skincare routines because your skin's needs differ between day and night. Your AM routine prepares and protects your skin for the day, while your PM routine focuses on repairing and rejuvenating your skin overnight when its regenerative abilities peak.