When do you start to buy new born stuff?

I started buying after 20th week when I know the gender of my baby. I prefer to know the gender first so that it was easier for me to choose the designs of my baby's items. Some of the essential things that you can get before your baby's arrival: 1. Swaddle 2. A pieces of rompers. Do not buy too many as you may be receiving some during baby shower. 3. playpen as baby's bed 4. Mittens and bootees 5. Blanket 6. Baby mattress to be placed in the playpen 7. Baby wipes and diapers 8. Pump 9. Milk bottles 10. Nursing pads 11. Changing mat 13. Bathing tub 14. Wash cloths 15. Baby bathing soap