Kinda like the starter and battery are electrical, they could fail, might as well change them also...
Sorry dont mean to be a jerk, just dont see the point in replacing stuff that isnt bad for the sake of replacing it... I am not independently wealthy and am pretty cheap, I will spend money on good quality parts where it counts..... plus relays are piece of cake, it fails on ya, you pop the hood, swap it out for a non esssential one till you stop by the parts store and pop in a new one....