Zander is in his cot & will be moving to a new room soon (see my other post ) & I was wondering if a toddler bed is worth the money? The bed we have for him is my old one from before I moved out & is a king single, so quite big for such a little person. Would I be better off getting him a relatively cheap toddler bed & using his normal cot mattress or just getting rails for the king single?