Far too many people do this. Installing a bunch of useless mobile apps or browser extensions, and then granting them any permissions they ask for.
Right now, I rely on my anti-virus software to detect all the possible malicious attacks that can get to my device. IIRC, it also shows a notification if a certain program asks for permission. The thing I'm worried about is when it asks to have the file changing (permission?) towards the PC. That could easily be a red flag.
This behavior is also a huge privacy risk. Everyone should go through their phones, uninstall every useless or pointless app, and revoke all unnecessary permissions from the ones they are keeping.
This could help the user to be more organized, too, if you check all the applications that are less of your worries. Depending on the phone, look at the least used applications in your phone then act accordingly, removed. Storage and Memory savings. You better have control over your private information.
It's best to be prepared whenever you have sensitive data like backups of your files, phones, pictures, etc. You won't regret backing up everything.