You're welcome @Robin527
It depends where you are as to how much not using instant book will affect your bookings.
I am in London, England and there are so many listings as so much competition I have to have it on!
When I was new to hosting I had very loose requirements- I didn't bother with ID, previous reviews and so on as I wanted to get guests in to build my reviews and listings, after I did that I tightened up my settings and became more careful...not that I have had a single issue with any of my own guests so far!
I don't mind guests who are new to Airbnb (I was a new host once, and guests took a chance on my listing with no reviews)
The way a lot of hosts review guests often make reviews not that helpful with deciding if a guest will be good or not anyway, so I am happy to take a chance.