>once you work in a given place, there's usually not much choice which union you can join (or which will represent you in any case), and your only option is to

>once you work in a given place, there's usually not much choice which union you can join (or which will represent you in any case), and your only option is to change employer, location or career. Unions are generally democratic, too, so there's also the option of voting for different union reps (or volunteering to be a rep) in order to change the union's policy or how the union works.