I would be willing to bet your sales would be significantly better if you did not use DRM. I say this because I have seven books, one of which I enabled DRM, and it is the only one that doesn't sell very well. I would change the option if I could.
It no longer matters much whether we choose DRM or not. Most ebooks are now released in KFX format, which will be delivered to all the newer Kindle devices and apps. And KFX, unlike DRM, is pretty much unbreakable.
I would wager that 99 percent of ebooks are bought by people who don't know whether the book is DRM'ed or not. There is a minority of people who know these things, but most of them aren't much interested in actually paying for a book
All of my 17 NON-DRM titles ended up on mirror sites, where people could download them for free. ALL of them, EVERY single one, on multiple sites. And trying to get them removed, was like chasing a hydra with a plastic knife and a match. No success at all. Why buy the books when you can get them for free? I had to remove them ALL from KDP, re-edit them with new content, make new covers, and release them in paperback on Createspace,
This has cost me readers, and money. I don't agree with the 'payment per page read' subterfuge going on with KDP, but so many people read EBooks, I am being forced back into the EBook market. I will enable DRM on every book, EVERY single one. With the new changes and cover, if my books show up anywhere, then I can take legal action.
You can lose 1 or 2 readers per 10 gained with DRM, or you can lose all of your money on free downloads on book sites, there are hundreds of them out there, just like there are hundreds of mirror sites for watching pirated video, music and movies. Protect yourself. This is a caveat l'emptor tale to keep you from going through what I have, second time without DRM, shame on me.