Well, as the title says really! DS is nearly 13 months and sleeps in a cot which has wooden panels at the end. Several times a night, he will wriggle and flop around so that he ends up head butting the end of the cot loudly (we can hear it from several rooms away). Obviously I wouldn't have used cot bumpers when he was smaller but would it be safe to use them now? He's perfectly healthy and very robust (and very mobile) if that makes a difference!