My character, Keeva, carries a pocket knife. It isn't a defense weapon, it is just a tiny tool she learned to use as a child when hunting with her dad. As an adult with her own café, she still finds it very useful. Placing the knife in her pocket, with keys, cellphone, etc. became part of her daily routine.
In writing about her pocket knife, it reminded me of consistency. I went through the manuscript and checked for consistencies and inconsistencies. Like magic, the pocket knife appeared in a scene. Not very consistent of me, so I had to go back and write it in. I did this by placing it with her cell phone and keys, and made it her habit.
Sounds like a tiny element, but consistency in writing, needs to be like a habit. If your character has a quirk, in most cases the reader wants to see that quirk more than once, it needs to become part of their personality. But not so much it is annoying.
Does your hero put a nickname on the heroine? Or visa versa? Chances are you want to stick to one nickname and use it fairly regular. Recently, I read a book where the hero gave the heroine a nickname, and it changed halfway through the book. When I finally figured out what the writer did, I lost interest in the book.
If you find you need to check how regular a habit, name or some other particular you want to repeat (or not repeat), you can use MS word to look it up. I do it as a find and replace. For example, I had two characters with similar names, this ended up confusing me and I knew it would confuse my readers. I opted to change one characters name. To do this I went to the Home tab, selected Find/Replace and typed in the one name and replaced all with the new name.
Remember you can use highlight if you don't want to replace, and make sure you check the box for 'whole words.' This technique I use to find all my "TO BE" verbs. From here I can get a quick picture of passive voice, something my writing chronically suffers from. That can be another blog because it often means my Deep Point of View is lacking.
But remember you can use this same technique to find if you stayed consistent with a habit or quirk, a name or anything else you do or don't want repeated in your ms.