Other than making sure you buy a snowboard that is right for your height, weight, feet size, riding style and ability, there are few other things to look out for when searching for second-hand snowboards.
Check the top/deck for any visible damage. Delamination of the top-sheet can often be repaired but damage to the exposed fibreglass or even to the core of the board is not as easily rectified.
Make sure you remove the bindings from the board before you buy as they can sometimes be hiding cracks or other damage. Likewise, always ask that stickers are removed for the …