No one is perfect. Well, except Nadia Comaneci, and Torvill and Dean.
That doesn't mean we can't or shouldn't strive for perfection.
I take a great deal of pride in my grammar, spelling, and proofreading skills. I know that mine are above average, but I also know that the results of refining those skills are attainable by nearly every writer who dreams of uploading a manuscript to Amazon.
I finished the actual writing of The Looking-Glass Portrait on 11 July 2016. Because it was written using Word Perfect, I had to convert the document to Microsoft Word before I could upload it. There are certain conventions of the two softwares that are not 100% compatible, so I had to go through the entire manuscript and make manual corrections to things like em and en dashes, tabs and ellipses, double breaks and so on. This also gave me the opportunity to look in both versions for marked spelling errors and fix them.
Spell check tools are wonderful. They won't catch everything, but they catch a lot. Anyone who doesn't take advantage of them is just plain foolish. I've seen too many author-published works on Amazon that have clearly never been run through even the most rudimentary spell-checking program. This is unforgivable.
After putting my MSWord document through the conversion to HTML and then to mobi, I uploaded it to Kindle Direct Publishing on 18 July. Yes, just one week. No one else had read it. No one else had proofread it. No one else had edited it. I knew I was taking a huge risk that I might have missed something major, but I was willing to take that risk and trust at least to my own proofreading skills.
The uploading process contains its own spell check application. I used it, too, because you never know what the other programs might have missed. And they had in fact missed one typo that I was able to fix before uploading. I hit the "publish" button.
By Word Perfect's count, the book is something over 138,000 words long. After a few readers got back to me, we had identified a grand total of three -- three -- errors that escaped my eagle eyes: a missing space between two words, a wrong word, and a missing word. All were easily fixed so the corrected document can be uploaded to Amazon.
Am I bragging? Yes, I am! But I'm also saying that this can be done by anyone who is willing to learn the skills or learn to rely on others who have the skills. Your readers should be able to sit down with your book and read it, not correct it. Are three errors acceptable? Well, not by me! Would I throw a book against a wall for three errors in 400 pages? No, of course not. But I wouldn't read past the first page if I found three errors on it.
It's not enough to put your heart and soul, your blood, sweat, and tears into you book. You have to put your skill into it, too. Language is the absolutely essential tool you have with which to build your literary world, and if you don't learn to use it with consummate skill, you probably won't be able to tell a story people will be willing to pay good money for.