One of the (many) reasons I would make a lousy writer is that I hate revision and self-editing. This may seem contradictory when it's what I do for a job, but I cringe when I read my prose. When I'm reading someone else's writing, I have that sense of detachment that allows me to see what is and isn't working.
Do you enjoy revising your work? And when should you show your work to someone else for another opinion? Or indeed - should you?
The golden rule is - don't show your work to anyone else when they are likely to come up with a list of suggestions that you are already half considering. So if their comments are going to make you say things like 'yes, I thought that', or 'well this is only a rough draft', or 'I already know that needs changing', don't show them.
Showing a reader - whether a friend or relative, or an editorial consultant, a half-finished piece of work is frustrating for all concerned. The reader wonders why you are asking their opinion when you already know it, the author wonders why the reader is picking up on the 'obvious' stuff that they already know about.
You don't have to have a completed piece of work - you can show someone the first few chapters of a novel, but it does have to be at your best level. Your reader can then give you considered advice, rather than repeat what you already know.