Every writer has their own peculiar set of words that tend to be repeated too often. I tend to use ‘then’ a lot. I also have a few ways of wording things that are not efficient, nor particularly smooth reading.
In the initial draft, I just let it go. The goal of a first draft is to get the story down. Subsequent drafts are where corrections are made. I have to pay special attention to these repetitive tics and reword those sentences as I come across them.
That’s a part of maturing as a writer–recognizing your own tendencies that bring a manuscript down and dealing with them. Recognizing is the first step, and getting critique from somebody who isn’t afraid to point these tendencies out is an important part of learning about your weaknesses.
Only after the weaknesses have been identified can they be addressed. If you do a lot of self-editing, then it becomes doubly important to have some critique to help identify problem areas and what phrases you tend to over-use.
I typically do one entire read through a manuscript focusing on diversifying, clarifying, and generally improving the prose on the page. That is in addition to passes that look for white room description, continuity and consistency issues, and dialog.