Conwny on "Passive Monitors, Neighbors, and When to Relax"

Hello All. I would really appreciate an expert's opinion on the few questions I have. On the 14th my heat treatment was completed after realizing a used couch that hadn't even been in my new apartment for a week came with bed bugs. I've unbagged most of my things and I've ceased bagging my purse upon entering. I've tried to relax a bit as I've seen no fecal stains, live bugs, or any other definitive signs *knock on wood*. I have a Packtite passive monitor on my headboard, under my chair in the living room, and in my car. So far, no fecal signs *knock on wood*. Do you simply look for markings on the white part, or do you need to actually attempt to look inside the cardboard? That will be hard to do with the one on bed and in car. If I still had bed bugs, would they have left signs on these monitors by now? I worry they, if they're here still, already have a great hiding space in my wood headboard or under bed storage drawers. Besides the mystery bumps that showed up on my feet last week (dermatologist cannot determine if they're bites or just skin irritation-leaning more towards skin irritation), there have been no signs *knock on wood*. Tomorrow my PCO is coming for a follow up inspection and spray. When can I finally breathe a sigh of relief? Is it 30 days or 55? I've seen both on this forum.
Next, my upstairs neighbor told me, after I saw him for the first time after the PCO had to spray in all of the neighbor's apartments (it's a four plex), that he is pretty sure he had bed bugs in his old apartment, but "he bought all new furniture". I think he's been here for a few years. What if he has bed bugs, OR bugs have moved into other apartments? Should I talk to my landlord about this or the individual neighbors? Having learned WAY too much about this topic, it makes me really nervous to live in an apartment. Gah. Any thoughts?