Buddy wears his collar almost 100% of the time. It only gets taken off for a bath or a good brushing.
When he goes to the dog park, we put a harness on him and take his collar off.
If we had more than one dog, they would only wear collars and/or harnesses when they went outside of the house, it's too dangerous to have them on otherwise.
Buddy's harness has his name, our phone numbers and our address.
His collar has the same as above, his rabies tag and Get Me Home ID-just in case.