Hi Robert, In the AdWords API perspective, I can confirm that you can set your CrmBasedUserList object's MemberShipLifeSpan <https://developers.google.com/adwords/api/docs/reference/v201710/AdwordsUserListService.UserList#membershiplifespan> to "10000" which should translate to "no expiration". As for the AdWords UI, I looked further into the documentation that you sent and came across this guide <https://support.google.com/adwords/answer/6379332>, which under the "Membership duration" section, says that its duration is already unlimited by default.
However, since the AdWords UI part is already out of our team's scope, you may confirm this information with the product experts at the AdWords Community Forum <https://www.en.advertisercommunity.com/t5/Google-AdWords/ct-p/Google_AdWords#> as they are better equipped to provide you with the information you need. Best regards, Peter AdWords API Team -- -- =~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~ Also find us on our blog and Google+: https://googleadsdeveloper.blogspot.com/ https://plus.google.com/+GoogleAdsDevelopers/posts =~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~ You received this message because you are subscribed to the Google Groups "AdWords API Forum" group. To post to this group, send email to firstname.lastname@example.org To unsubscribe from this group, send email to adwords-api+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/adwords-api?hl=en --- You received this message because you are subscribed to the Google Groups "AdWords API Forum" group. To unsubscribe from this group and stop receiving emails from it, send an email to adwords-api+unsubscr...@googlegroups.com. Visit this group at https://groups.google.com/group/adwords-api. To view this discussion on the web visit https://groups.google.com/d/msgid/adwords-api/a7e5d3cb-043a-43d1-a678-e66b78e5ce05%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.