Bugzilla

Below is an initial proposal to UX. It is a combination of many of your suggestions.  "remind me later" wording comes from aleca.  I added "Not now" for additional clarity, but if it is deemed unnecessary I'm happy to see it dropped. 

Please bear in mind that with a dozen or more people interested in this issue, it is not possible to incorporate wording that everyone will agree with - so compromise and flexibility is necessary.  

Reiterating a previous idea, brevity is essential in dialogs - in part because we can't adequately convey the complexity of this function to users, nor do most users need it. And more words and complexity often generate confusion. So if there is a shorter wording that conveys the same information, I'm all ears.   

Side note, in bug 1718443 it is proposed to expose the prompting preference, so that it can be toggled independent of the compact prompt.

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Thunderbird needs to perform routine file maintenance to recover xxMB of disk space. This maintenance is needed periodically to optimize storage for better performance.  To let Thunderbird do this automatically in the future without asking you, select the option below then click Proceed. For more information: <link to Help Article on compacting>

 (Proceed)               [ ] Do not ask me in the future
 (Not now, remind me later)
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Thomas, aleca, please weigh in

Below is an initial proposal to UX. It is a combination of many of your suggestions.  "remind me later" wording comes from aleca.  I added "Not now" for additional clarity, but if it is deemed unnecessary I'm happy to see it dropped. 

Please bear in mind that with a dozen or more people interested in this issue, it is not possible to incorporate wording that everyone will agree with - so compromise and flexibility is necessary.  

Reiterating a previous idea, brevity is essential in dialogs - in part because we can't adequately convey the complexity of this function to users, nor do most users need it. And more words and complexity often generate confusion. So if there is a shorter wording that conveys the same information, I'm all ears.   

Side note, in bug 1718443 it is proposed to expose the prompting preference, so that it can be toggled independent of the compact prompt.

---
Thunderbird needs to perform routine file maintenance to recover xxMB of disk space. This maintenance is needed periodically to optimize storage for better performance.  To let Thunderbird do this automatically in the future without asking you, select the option below then click Proceed. For more information: <link to Help Article on compacting>

. . . (Proceed)               [ ] Do not ask me in the future
. . . (Not now, remind me later)
---

Thomas, aleca, please weigh in