An editor has the ability to put a rough edge in a sentence into context, so it sounds just right. Take for example this:
“…looked like costing $150,000 and one year ago when Mr B___ took charge of the project, with much able assistance from technician and friend M__ B____, he knew $150,000 would not arrive on his doorstep.
This is rough for only one reason. I mentioned $150,000 twice, but a careful editor would change that to sound like this:
“looked like costing $150,000 and one year ago when Mr B___ took charge of the project, with much able assistance from technician and friend M__ B____, he knew that price would not arrive on his doorstep.
The editor contextualized the $150,00 figure by referring to it as that price later on, whereas the unedited version had mentioned the $150,000 figure twice in the same sentence. Now, it sounds better, when $150,000 is referred to as that price later on in the sentence. Again, thank you editor.
Talking Writing 