This article states how to change the TTL for a saved search individually: https://docs.splunk.com/Documentation/SplunkCloud/8.2.2105/Search/Extendjoblifetimes I want to change the default TTL of any and all saved searches. Otherwise, I and my team have to remember to change this for each new search we save.
You can accomplish this by adding a [default] stanza to savedsearches.conf and adding dispatch.ttl = your_value_here under it. Where your_value_here = time to live in seconds.
At the application level, Include the updated savedsearches.conf in $SPLUNK_HOME/etc/apps/<app_name>/local
For a system level change place savedsearches.conf at $SPLUNK_HOME/etc/system/local. Though this is NOT recommended.
Documentation is here under 'dispatch search options' :https://docs.splunk.com/Documentation/DFS/1.1.2/DFS/Savedsearchesconf
Also, if you do add dispatch.ttl to a [default] stanza, then you would need to remove that setting from individual search stanzas as those would override what's in default.