I always believe that every quilter should use whatever works for him/her. But since you asked... I do leave some pins in if I don't need to remove them to quilt where I want to quilt, but not all of them. I took a class with Cindy Seitz-Krug & she talked about the importance of SITD before beginning FMQ. I really couldn't see why that would matter -- or how I could get it to look nice without leaving invisible (synthetic) thread in my quilt -- but lo & behold, switching to a wash-away thread to SITD before I began my FMQ truly does make for a nicer, more uniform quilt & the seams lay nice and flat.
The other thing is that I try to pin every 4" or so (width of my fist) because otherwise I get puckers and bunching in the back. But that's on my machines (1975 Singer Genie & my new Bernina 350). You might be fine pinning farther apart (and I'm only assuming you are basting every 8 inches based on what looks to be 4" blocks).
Either way, those are nit-picky details & the most important thing in quilts that aren't being made for sale or for competition is that we enjoy the process of making them. I definitely have cheated when making family quilts & you can see the results of those cheats if you are within a foot of the quilt, but they are beautiful quilts and my family members love them no less.