So, I took on a charity consulting case of a site that really and genuinely has great content but was hit by Panda two different times several years ago. The people who run the site are not SEO savvy and were unaware of the Panda issue. All they knew was that they had dramatically lost traffic a few years ago and then about 6 months after that they had another dramatic loss of traffic leaving them with only about 10% of their previous traffic levels. Because they did not know much about SEO, they never knew that the traffic drop was related to Panda and had assumed that a theme change that also occurred close to the traffic loss was the culprit. They simply left the site as is for years (other than adding new content) until I came along. This site is also attached to a print magazine, so they had that luxury.
Both traffic drops coincided with known Panda updates so I am 100% sure that the problem is a Panda one. The site has very good content (good length, engaging topics, well researched and written, professional sources - the whole nine yards) but the site was a mess in terms of some pretty common Panda issues that were caused by WordPress, such as thin pages, duplicate pages, slow load times and the like. We have since cleaned it all up and the site does have a strong presence on social media sites.
Now, I have pulled my own site out of Panda two different times (affected due to issues related to the ones listed above) but that was back when Panda still had update dates, so it was just a matter of waiting until the next update. But now Panda is part of the rolling algorithm. About how long should I wait before deciding that the work done is not enough? I personally told them that the theme should probably be replaced as well (they were unaffected by Panda prior to the theme change), but they consider that a nuclear option and really don't want to do that. Do I wait 3 months, 6 months, 12 months or ? months before insisting that they consider a theme recoding as well? How long, on average, does it take to recover from Panda these days?