Sometimes you hear people say that as long as your seam allowance is consistent, it doesn’t matter if it’s ¼” or not. I don’t think it matters if it’s an exact ¼” or scant ¼” either, but in some patterns it really matters how much of the fabric is taken up by that seam.
I wrote up a sheet to show the tools I used to get my seam allowance in quilting. I keep my extra bobbin cover and my ¼” foot together, and pull them both out if I’m piecing. I always use the same thin thread for piecing as well, because if you use thicker threads, they take up more of the seam allowance. In many quilts it won’t matter so much, but if you get more intricate patterns, with more seams, in different directions, it might matter a lot! This works for me.
Keep thread and pins away from your helpers, no matter how much they want to learn!