in terms of wire, its preferance as long as it meets the current requirements. I wouldnt want to use stranded wire on a board though... especially on a bread board. I ran out of jumpers and had to finish a project with hook-up wire. not fun. Use stranded wire at times when the wire will be flexed repeatedly, and in higher current apps. you are going to have to plan out the chassis of your bot before you can figure out what kind / length / thread you need for the fasteners.