I have a 15 pound Poodle mix rescue mutt that doesn't shed. I used to imbibe in a bit of bud in my listening area, but I managed to quit some time ago. We are empty-nesters but have constant visits from grandkids. So when I have sold or advertised items on CL, I never say smoke, pet or kid free. The equipment, however isn't really affected by any of those three detriments.
Should we care if a piece of equipment comes from a pet-free, kid-free, smoke-free home?
I agree that I do not want a preamp or speaker coated with a film of smoke, but I am confused as to what a child or pet could do that would not be otherwise visible. You would see the cat scratches on the speaker grill, the dog chew marks on the rack, the iguana turds in the amplifier cooling vents. And what's a little dog hair among friends? As a 3 year old, I supposedly put my finger through my grandfather's new DIY speaker but I'm pretty sure he replaced the drivers so even that doesn't really matter. Most things will be visible and/or easily remedied. Maybe the price will even be a little lower because of the cosmetics. If it doesn't mess with function, not a big deal to me.
What concerns me more is does it come from a drunk-free, drug-free home. I think befuddled owners are far more worrisome than pets or children.