I like to at least bleed the brakes and remove any debris or contaminants. I change out the brake fluid by syphoning out old and adding new insuring I am keeping the master brake cylinder at least half full, never let the master cylinder go dry. Do the same with power steering fluid also.
Good video on bleeding brakes by yourself.
https://www.youtube.com/watch?v=V5O...ex=3&ab_channel=felixtcat1felixtcat1