Even if you use a punting smartphone and never connect to your civvy phone by email, sms, voice , twitter you can still get caught out by meta data.
Recently I installed Linked-in as the a provider uses that to communicate.
A few days later using Linked-in at work I received a Do you know <Insert my punting phone email add> ?? You could have knocked me over with a feather.
Looking further into this the Linked-in app has grabbed location data and cell tower data, local WiFi hotspot data, bluetooth data and cross referenced me and my punting self through Linked-in. I'm not too worried as they just want to scan your contacts and monetize you. What worried me is that it seems to have done this automatically and what 3rd parties they might sell the data to
So be careful about using the same bluetooth in your car with your punting phone and own phone on same shared WiFi if you use apps like Linked-in, Whatsapp, Facebook etc. Make sure the apps don't run in the background. Best never let your punting phone enter near where you live or work when switched on.
I've created new emails, phone number, AW id etc that I use for punting