I bought a book last year that discusses exactly this topic and mixing and matching machine quilting with hand on the same quilt. No reason not to do it. I do both. I am brand new at LA quilting and only now working on my very first quilt top. I had done smaller quilts on my Bernina doing SID and FMQ. I have mixed the two on wall hangings and it looks fine. I do find I have much more control in handquilting and have hand quilted very elaborate designs that I would never attempt with a machine, like this dragon pictured below. I like both equally well. Machine quilting goes a lot faster than hand, that is for sure.
One thing the authors suggested when doing both is use machine quilting in borders and hand quilted motifs in the body of the quilt but that was just one application of mixing and matching the two techniques.

some of the quick turns are really hard on a radius I can achieve with the sewing machine.. when I use the machine.. no curves are involved ! that is just me.. Parkinsons has it's own challenges at sewing ! <grin>

Thanks for asking this! I was just going back and forth with this idea for a wall hanging for a friend. I already did SITD to outline the blocks, but was contemplating attempting some hand work to accent the individual pictures inside each block (it's a cheater panel with a gingerbread theme).

feline fanatic - that is some amazing hand work! I have never really done much with hand quilting, but want to try... I didn't know if a more complex design would get "lost" since the stitches aren't continuous like with machine quilting. Good to know it can be done!

When hand quilting I like to use a cotton batt, or 80/20. I love the look of it.

I've both hand and machine quilted on the same quilt. The best example is an irish chain. I hand quilted in the plain blocks, but machine quilted across the "chains" because it is difficult to hand quilt thru so many seams. Looked fine.

I usually use the thread that matches the quilt the best. My hand stitch isn't good enough that I want to use a contrasting thread.

Your hand quilting is amazing! Beautiful work!

So what seems right to you. No quilt police here.

I've hand quilted a few quilts and never tried machine quilting, which is why I hope to get my hand in machine quilting by starting it small. I actually intend to outline some quilt block patterns using SID. When machine quilting using the backstitch method when locking stitches, is it advisable to start right at the top? If my block patterns are smack in the middle of my quilt, can I still use the backstitch method? The backstitches might be quite visible, which could look unsightly.

Last year I made my son and new daughter in law a quilt, I love to hand quilt, but I am soooo slow, and I wanted them to have the quilt before their 10th aniversary! I had it machine quilted, but had her leave the appliqued center unquilted. When I got it back, I finished the center with hand quilting so that they would have a little bit of my hand quilting on it.