I have utilized both Road ID wrist/necklace styles. I prefer the necklace style over the wrist because the velcro band on the wrist style was always irritating and "itchy". It's a terrible thought, but often times in traumatic accidents a persons shoes can be knocked right off their feet. I think the necklace style might offer more security as far as retaining ID. in any type of serious accident. The Road ID website www:RoadID.com has great advise and info. One thing they recommend is incorporating your City and State of residence...BUT not the actual physical address. The saved space can be used to add more useful information/contact numbers. This is pasted from their website:

"if you need room to list other important information on your Road ID, you can easily omit your Address - it's just not that important. Why? In the event of an accident, you Name and Emergency Phone Numbers are going to supply the first responders with the majority of the information they need. If, for some reason, the authorities need to locate your home address, they will be able to easily find it with your Name, City and State - all of which should be on your ID. If, however, you want to list your street address, please feel free to do so."www.RoadID.com