It's all well and good to self-publish your own works. I did ten Jazzy books with not so much as a "What do you think of this?" question to colleagues. Granted, I didn't know anyone then, but I should have asked.
One of the most important lessons an author can learn is to be open to criticism. Two years ago, I wouldn't have been capable of handling it. Now, it's like being handed the pickax to dig out the vein of gold that is staring you in the face.
I thought my book, Princess Jazzy, was ready to go. I had several people view it and they fixed some words and things and, of course, Jazzy's so cute it's easy to overlook bad writing.
More important than getting feedback from others, though, is finding the "right" others to give you the feedback. My hubby, my daughter, my friends in an adult book critique group, and a few beta readers all said they loved it.
Then I shared it with two professionals.
I dropped my ax and looked hard at what I thought was gold. There was gold in there but it was behind several layers of fools gold. Yep, I was digging in circles and not getting to the real thing. My two professionals set me straight, thank goodness.