Getting another set of eyes on that manuscript is vital. Sometimes, we think we wrote something in a certain way, but for whatever reason, what we thought we put on the page isn't what we actually put on the page. Sometimes, we get too close to our stories that we can't see the forest for the trees. Without having that external input, vital issues easily slip through the system.
It can be a costly venture to employ a developmental editor, something that can be beyond the budgets of many writers. But a developmental editor is NOT the only way you can get that vital feedback.
Every writer I know, myself included, uses critique partners and beta readers as part of their editorial process. However, there seems to be some confusion about what these two types of readers do.
It's time to delve into the nitty-gritty as to what makes a critique partner different from a beta reader.