Purrley, I would say to keep the collar on
all the time for ID tags/Rabies tag, etc,
and use the harness for outside walks.My
daughter uses a harness on her 65lb dog b/c
he does tend to pull on leash.They work
great & as MHMamma says it give you more
control & you can scoop them up easier if
in danger. Harness would definately not
work on my Buddy, just for the heck of it,
I measured his chest/rib area the other day
and he's 38inches around.Don't think they
make em that big.Anyway he's a large breed
with very strong neck muscles, so I use
only the collar.