Enrolling your ebooks in Amazon Kindle KDP Select exclusivity can definitely increases sales
However, from my experience of having my ebooks in and out of KDP Select exclusivity many times, I have to say that the benefits only last so long.
While the first 90 day period always results in a sales boost, for each recurring 9o day enrolment period, sales and KENP page reads gradually fall away.
I have now had my all of my ebooks in KDP Select for three consecutive 90 day periods but I am in the process of removing my ebooks from KDP Select and moving back to open publishing over the next month.
The reason is exactly the same as my previous times with KDP Select.
After about six months, sales fall away.
This time, however, I also noticed a dramatic decline in KENP page reads during the last three months of enrolment, as the graph below clearly shows.
While it is impossible to know the precise reasons why this decline has happened every time I have been in KDP Select, it is probably a logical assumption to say that it is due to Amazon’s algorithms, and its need as a retailer to promote fresh products.
I have to say, though, that re-enrolling after a break of six months or so seems to get some type of reward from Amazon, as sales always increase again.
How does Amazon promote KDP Select ebooks?
Getting accurate data and information regarding how Amazon promotes KDP Select ebooks is impossible, so experience and anecdotal evidence is all I can bring to this topic.
But after five or six times in and out of Amazon exclusivity, I can honestly say that I believe the benefits of KDP Select diminish towards the end of the second enrolment period, and then decline further in the third.
As Amazon only asks for 90 days of exclusivity, perhaps this in itself explains the sales drop-off.
Amazon obviously needs to reward publishers for granting KDP Select exclusivity. Otherwise, there would be no point to the exercise.
So, perhaps Amazon is only prepared to reward for a certain amount of time, which would explain why the required exclusivity period is quite short, and why the consecutive second and third enrolments are less successful.
Whatever the reasons, I can only offer my conclusions on KDP Select from my own experience.
Firstly, yes KDP Select certainly does increase sales and page reads in the initial 90 day period.
Secondly, there is still benefit in a second consecutive 90 day period.
But lastly, leaving your ebooks permanently enrolled has limited benefit, and that returning to open publishing may be a better option.
That is the route I am taking at present through Draft2Digital, but I will certainly return some of my ebooks to KDP Select exclusivity in the future.