No collars on unless we're going somewhere. Had a scare years ago with my parents dogs that made me decide this. They were wrestling and one got his canine tooth stuck in the others collar, they were twisting around all over the place but couldn't get loose. Both were basically being strangled to death and my dad had to cut the collars off (thank god we were there!). Bad bad bad. None of our dogs have ever worn collars since! Mine are all microchipped, FWIW.