Guidelines must vary detween countries as, in the UK, quilts, pillows, etc are considered ok from 1 year. My dd has had a pillow from around 12 months as she had a cold at the time and the pillow helped to elevate her head and helped her to breathe a bit easier. I used an ordinary sized quite flat adult pillow in the cot - it fitted well and left no spaces between itself and the cot bars.