Many people do not realise that these are both essential elements in the process of producing written work. Time for these needs to be included in a writing schedule. It is all too easy for the eye to see what it wants to see and not what is actually presented. Using the wrong word in writing can easily happen especially when words sound the same(homophones).
Proofreading, for example, checks that the words it’ s (it is), its (the possessive pronoun) or i’ts (a meaningless word) are not confused. The example given is a common error. Mixing these and other words up without correction shows the reader that no care has been taken to check the written work. It can also indicate that the writer does not understand English, its grammar and syntax.
Editing is a more complex process. The author of this blog has a great deal of experience in producing written work. Even so, the process of editing the paragraph above, consisting of eight sentences, and this paragraph, took time. Words were removed or replaced and the order of phrases and sentences was changed in order to improve the flow of logic. An experienced writer has sufficient practice to be able to carry out simple edits during the ongoing creative process. Writing on a computer has the advantage of cut and paste, undo and redo. That is why it is not possible to state how much time was required to edit this writing.
What can be stated is that care was taken and the entire piece was carefully re-read after a lapse of time before posting. It is always better to take a break away from the written work before commencing proofreading and editing. That is why the on-going editing process (while writing the piece) is not sufficient. A break away from the written piece reduces the risk of including errors. Asking another person who understands the process of proofreading and editing to check over the written work is the best option. (And, yes, I did that too!)