Changing default passwords & setting strong ones are important for routers & security devices — as neglect in that area can lead to compromised security.  It is also important to manually rotate passwords — even if device allows for a permanent one. 

NSA Best Practices for Selecting Cisco Password Types | CISA

CSI_CISCO_PASSWORD_TYPES_BEST_PRACTICES_20220217.PDF (defense.gov)

The National Security Agency (NSA) has released a Cybersecurity Information (CSI) sheet with guidance on securing network infrastructure devices and credentials. Cisco devices are used globally to secure network infrastructure devices.  Credentials within Cisco configuration files could be at risk of compromise if strong password types are not used. The CSI reviews Cisco’s password type options, the difficulty to crack each password type, and its vulnerability severity and provides recommendations for use.  CISA encourages administrators to review NSA’s CSI: Cisco Password Types: Best Practices and consider the recommendations to secure sensitive credentials.