1. Purpose: Determine the mask's intended use (e.g., medical, fashion, construction).

2. Material: Check the material for breathability and effectiveness (e.g., cotton, polypropylene, N95).

3. Fit: Ensure it fits snugly over the nose and mouth without gaps—consider adjustable ear loops or ties.

4. Breathability: Look for masks that allow for comfortable breathing without compromising protection.

5. Layering: Opt for masks with multiple layers for better filtration.

6. Reusability: Decide if you want disposable or washable/reusable masks, and check care instructions.

7. Design: Consider the style and print that align with your personal taste or occasion.

8. Size: Make sure to choose the right size for adults or children, especially in fitted masks.

9. Certification: For medical masks, check for certifications like N95 or ASTM ratings for effectiveness.

10. Comfort: Look for features like nose clips and soft ear straps to enhance comfort during extended wear.

11. Compliance: Be aware of local regulations regarding mask-wearing in public places.

12. Odor: Ensure the mask has no unpleasant odors, which can be a sign of low-quality materials.

13. Storage: Consider how you will store masks when not in use; a clean, breathable bag is ideal.

14. Price: Compare prices but beware of very low-cost options that may compromise quality and safety.

15. User Reviews: Check reviews or ratings to gauge other users' satisfaction and experience with the mask.

16. Allergies: Be aware of any allergies you might have to materials used in the mask.

17. Visibility: If you’re using a mask for activities like biking or running, consider options with reflective materials for safety.

18. Eco-friendliness: If concerned about the environment, look for masks made from sustainable materials.

By considering these factors, you can make a more informed decision when purchasing masks.