The level of reasonable care required varies, depending on whether you are an adult, child or professional.
Reasonable person standard - An adult is guilty of negligence if he or she fails to act the way a person of ordinary intelligence and judgment would have acted in similar circumstances.
Reasonable child standard - Both a child and his or her parents can be held liable for a child's wrongful conduct. Children, however, are not held to the same level of care as adults. A child's conduct is measured against what would be expected from a similar child of like age, intelligence and experience under similar circumstances. Because a child does not have the same mental capacity or life experience as an adult, the courts recognize that in some instances a child should not be held responsible for otherwise "negligent" behavior. For this reason, children of very young ages generally cannot be held liable for negligence. The judge will decide a child's capacity for negligence. If the child is deemed capable of negligence, then the issue of whether or not the child actually was negligent will be decided by a jury.
One major exception to the rule is that a minor will generally be held to an adult standard of reasonableness if the child is engaging in "adult" activities. For the most part, a child will only be held to this standard in situations in which the child is operating a motorized vehicle.
Professional community standard - Professionals (lawyers, doctors, architects, engineers, psychiatrists, etc.) are held to a higher standard of care due to their specialized training and experience. Professionals and individuals who practice "skilled trades" (plumbers, carpenters, electricians, beauticians, etc.) may be found to be negligent if they do not exercise the same degree of skill and knowledge normally exercised by other qualified and competent members of their professions working in their communities.