When a user authenticates with IMS, the length of time that you'll maintain access to the follow on application varies.
For sessions which originate inside of a web browser, the session is valid for one hour of inactivity and 24 hours of activity. Note that this session is issued to the browser, not a specific tab or window. Expiring the session in one tab will expire the session for that browser.
When authentication is performed in the CONNECTION Client, a session is issued to the browser inside the CONNECTION Client. This still expires as normal. However, CONNECTION Client only needs the SAML token to keep you signed in to the app. Tokens issued to the CONNECTION Client are valid for the next seven days. After six days, the CONNECTION Client will automatically attempts to get you a fresh token silently; you'd only need to authenticate again when that refresh fails.
Sessions issued between web browsers and CONNECTION Client are not shared. You will need to authenticate in both spots.
Applications which utilize OIDC as an authentication protocol may maintain your authentication using an optionally requested refresh token issued to the application. This refresh token lasts for 30 days and can be used to get fresh access tokens which are used to keep you signed into the application. After 30 days, you would need to reauthenticate again. Not all OIDC applications use refresh tokens and ones that do can be identified when the application requests the scope "offline_access".