Just stop using your electronic devices. Not like they don't all have monitors built in already anyway. Every connected device could be sending screenshots home and we'd never know. I mean, I guess you could use something like Wireshark to monitor your home network, but something tells me nowadays there are ways around even that. I'm not a certified network tech or even a script kiddie, but I don't trust my tech as far as my dog can throw it. I just try to secure through obfuscation as much as possible. Everyone thinks I have carbon monoxide poisoning, but it's a small price to pay for peace of mind - even a small one.