Proofreading is a necessity for any writer.
And you should proof to the best of your (and the Internet’s) ability before you send it to anyone else to read. Even your Beta readers or your Mom. They may not say anything but they’ll notice. Probably.
What is proofreading? It’s checking the basics. Are the words spelled correctly? Is it the right version on the word? (to, too, two for example) Has a word been left out of a sentence?
Maybe you used a word you didn’t mean. Spellchecking programs will not always catch these. Especially if you leave the “l” out of the word public. Cringe.
It happens, even after you’ve read over your own work ten (or more) times. You’ve looked at this piece over and over again and your brain is filling in the words that you meant to write. That’s why I recommend you find someone else to proofread for you.
Your proofer should catch oversights like these for you before your work goes to print. If you’re proofreading for yourself, give your eyes (and your brain) a break from looking at the same text it just created.
How much time? It varies from a few hours to a few weeks. In my opinion for the best results, you need to fill that time with something non-writing related.
I’ve had my work go to an editor and then to a proofer. They each knew the lines of their duties and didn’t cross them. But some presses have one person that does both.
When it comes to some vanity presses, you’re on your own because the publisher tells you upfront that your work will not go through a proofing process before it goes to print. Same goes if you’re self-publishing. If you find yourself responsible for your own proofreading, read and re-read the text or ask a friend that will be honest with you to read it.
A friend commented once during a writer’s dinner out: “Get someone to read your work that doesn’t like you and hasn’t slept with you.” (Well, he didn’t use the term “slept with” but I have to edit myself before I put these posts up. But more on editing in the next segment.)
But I agree to a certain extent. Find a proofreader that won’t hold back on corrections. Even if the paper fills up with red ink or the screen gets overloaded with tracked changes. And don’t be offended or discouraged if your work is returned to you that way.
It may save you from having your mistakes seen in “pubic”.