This is the best attitude if you have a smartphone. You will never, ever know whether you have a Remote Access Trojan installed that can turn on and off the camera and microphone, monitor your GPS location, look at your unencrypted messages, e-mails, browser history and saved images. There are some that can even insert messages to make them look as though they originated from you and modify browser history.
Droidjack is just one example, inexpensive and impossible to detect. Popular with suspicious spouses.
RATs can be installed via many routes such as malicious hyperlinks, fake public WiFi hotspots and convenient free charging points.
Despite popular myth iPhones are not immune.
https://www.bbc.co.uk/news/technology-49520355