This depends on how likely you are to damage your phone. If you're always incredibly careful and use a protective case and screen protector, your phone will likely survive most drops. However, phone insurance is definitely worth it if you never use a protective case or screen protector and drop or lose your phone regularly.
If you don't want to bother with insurance, back up your device regularly. Most mobile carriers let you back up things like contacts and messages. Your Google account can sync with Google Drive to back up files and photos automatically, though you may need to buy extra storage. If everything is always backed up, then you won't have to worry about losing important photos or files in the event your phone is damaged.