Flat head (positional plagiocephaly) is something a lot of mums worry about, and from what I've seen, many babies do round out quite a bit once they start sitting up, crawling, and spending less time lying in one position. That said, whether helmet therapy is needed really depends on the severity, so it would be worth bringing your baby to the PD to get a proper assessment before making that call. Some cases are mild enough that repositioning exercises and more tummy time are sufficient, while others may genuinely benefit from a helmet, so hearing from the doctor first will help you weigh whether the cost is justified for your child's specific situation. Going to the PD with your concerns will give you a clearer picture rather than worrying without a proper evaluation.