I learned this valuable lesson early on in my quilting journey. I made some placemats for my mom that were quilted very sparsely. When I went to visit her, I found them in her linen closet and they were an ugly wrinkled mess! She thought she ruined them the first time she washed them and tucked them away in the closet. I don't blame her for tucking them away, they looked awful and I assured her she did nothing wrong, it was all due to me not quilting them enough. I tend to fall in the same camp as shorttimer, if I don't quilt something to death I certainly do strive for putting them on life support. Especially something that will be heavily used. At least for my own quilts, quilts done for others all depends on wants, budget and look. But I definitely try to adhere to "no more than a closed fist" spacing in all directions. About the only exception is a narrow sashing, I will ditch it but may not put any quilting in it. Most pantos (E2E designs) have spacing not more than 4" apart.