My FurKids wear their leather collars, WITH TAGS, 100% ALL the Time -
without exceptions - even for baths & brushing!

I put it on when we are going out, either in the car or for a walk.
Once we return, I take the harness off again.
When they go out in the back yard to do their business, no harness.
There's way too many situations that can crop up - even when you're all home -
to take the chance of one of them getting loose or lost without their ID
AND a way to hold onto / secure them if required.
Consider:

* You're away and a burgler breaks in - door's open, he runs out of treets, and the Dog Takes Off.

* You smell smoke in the night - after you call the FD - are you going to gather the Gang
to "collar up" before fleeing out the door?

* Someone rings the bell - you open the door and Fido spots the Bunny out in the yard - *Zooooom!*

* These may seem far-fetched - but Stuff Happens!

On the *rare* occasions when I take a collar off (like to change license tags) -
the FurKid who's had his/her collar removed becomes quite agitated and won't
take their eyes off "THEIR" Collar till it's returned.

To me, it's NOT worth the risk that a Beloved FurKid could get lost and not be
able to show his "finder" where he lives.
TAGS save lives! --- Wear it!!