The Scor-pal is probably one of the best investments I've made in my stamping supplies. It really takes the "guess work" out of getting the folds in the right spot for gate fold cards or tri-fold brochures. PLUS, you can use it to make a grid design on plain card stock to get it some texture.
This is one of the gate fold cards I made for a Fun Shop.
All TAC stamps & products used here.