I depends, I suppose, on what you cut. I tend to use it a lot on my 'fine' work, but have also used it on things with 'bigger' holes. I have used emery boards cut to size before too. You'll find what suits you and the work that you do over time, we all do. I usually use 3mm boards in the main, but also 6mm. Anything 'thicker' I usually sand by hand or with a 'detail' sander. It won't however, smooth an 'uneven' cut, I suppose you'd have to do that by hand. Here's one with a lot of fine 'inside cuts' and I find it works well with this type of work. The horses are 3mm and the gorilla is 6mm.