I like to be able to work a bench from both sides. Thus, the width for me which is comfortable is 26 1/2". But, length? As long as possible, basically. Most important is how the bench will hold your work. On my 2 main benches, I have traditional tail vises, and love them! One has an Emmert No. 2, and the other an older Richards Wilcox gravity drop half nut quick action. Both are good vises.