Unusual battery drain
Phone overheating when not in use
Sudden spikes in data usage
Unknown apps installed
Apps opening, closing, or crashing by themselves
Pop-ups or ads appearing unexpectedly
Calls, texts, or emails you did not send
Contacts, messages, or files missing or changed
Strange account activity or login alerts
Settings changed without your permission
Microphone, camera, or location indicators turning on unexpectedly
Poor performance or frequent freezing
Phone restarting on its own
Unfamiliar devices signed into your accounts
Security warnings from your phone or apps
Passwords no longer working
Forwarding rules or permissions you did not set
Suspicious links or messages sent from your number
High phone bill or unknown charges
Device behaving differently in safe mode
Antivirus or security scans detecting threats