Dreadlocks started by Permrolling/Twisting are delicate. The biggest concern is that the hair will un-twist before it really begins to lock. This can make the palmrolling/twisting method pretty tedious and nerve racking. Because it's difficult to wash the twists without them un-twisting many people avoid washing their hair and scalp for a month or even more. This leads to other complications like itching or unusual head odors.
This may be the cause of many dreadlocks rumors related to washing or rather not washing dreadlocks. Two weeks or so between washings is more common. If your scalp is already comfortable with infrequent washing, maybe because it tends to be dry, and your hair is fine and highly textured, the ideal dreadlock texture, you may find that your twists hold up pretty well, especially if you are careful with them.