Different people have dry, oily, mixed, or sensitive skin. Your skin type may not suit a product for a buddy.
Your acquaintance may have different skincare goals. Their products may address issues you don't have or exacerbate them.
Some people are allergic to certain components. Using the same products may cause irritation.
Your acquaintance may have distinct skin due to climate. Humidity, pollution, and altitude affect product-skin interaction.
Age and hormones affect skin health. Your friend's skincare needs may vary by age, hormones, or life stage.
Your medications may interact with some skincare ingredients. If you have different health issues or use medication, what works for your friend may not work for you.
Skincare products vary in concentration. Your friend's active component concentration may affect efficacy and side effects.
Your acquaintance may have a skincare routine that suits their lifestyle. Without considering your schedule and habits, copying their routine may not work.