To access the account object in Salesforce, users need to have permission to the account object on their profile or permission set. Permission to an object determines what users can do with records of that object, such as create, read, edit, delete, view all, or modify all. If users do not have permission to an object, they will not be able to see or access that object in Salesforce. Reference: https://help.salesforce.com/s/articleView?id=sf.users_profiles_permissions.htm&type=5

The likely cause for why a rehired user is no longer able to access records they worked on before leaving the company is that the records were manually shared with the user. Manual sharing allows granting access to individual records to specific users or groups. However, manual sharing is removed when a record owner changes or when a user's role changes. When a user is deactivated, their role is removed and any manual sharing involving that user is deleted. When a user is reactivated, their role is restored but manual sharing is not. Therefore, the rehired user will not have access to records that were manually shared with them before deactivation. The stage of Opportunity records, permission sets, or record type of Opportunity records are not likely causes for why a rehired user is no longer able to access records they worked on before leaving the company. Reference: https://help.salesforce.com/s/articleView?id=sf.sharing_manual.htm&type=5

Two functions that an administrator should use when creating a validation rule are:
Error condition formula, which defines when an error should occur based on record fields and values Error message location, which specifies where on the page layout an error message should appear when triggered by an error condition formula Formula return type and rule active date are not functions used for validation rules. Reference: https://help.salesforce.com/s/articleView?id=sf.validation_rules_overview.htm&type=5

Maximum invalid login attempts, password complexity requirements, and number of days until expiration are three password policies that an administrator can configure to encourage employees to choose secure and appropriate passwords for their Salesforce accounts. Maximum invalid login attempts determines how many times a user can enter an incorrect password before being locked out of Salesforce. Password complexity requirements determine how complex a user's password must be based on criteria such as length, case sensitivity, alphanumeric characters, etc. Number of days until expiration determines how often users must change their passwords. Reference: https://help.salesforce.com/s/articleView?id=sf.security_password_policies.htm&type=5

The Stage Setup Flow is a tool that allows administrators to customize stages for leads and opportunities based on best practices from Salesforce experts. The Stage Setup Flow guides administrators through a series of questions about their sales process and then creates or updates stages for leads or opportunities accordingly. The Stage Setup Flow also provides tips and resources for each stage such as key fields, guidance for success, reports and dashboards, etc. Reference: https://help.salesforce.com/s/articleView?id=sf.stages_setup_flow_overview.htm&type=5