Each student in my class is assigned a number. I print several label pages with just student numbers on them to use throughout the year. (See my recent post on using labels in the classroom here.) I attached a numbered labels to the top of index cards and wrote in the student names. The cards fit perfectly in the pockets to designate what job each student is assigned to.
I try to switch the jobs weekly, but let's be honest, it often is 2-3 weeks before they get switched. I give more time so students get to know their jobs. It would also be a super extra hassle to try to change jobs daily. I just rotate them in order. I do have to do some fudging for the jobs like "girls bathroom pass" and "boys bathroom pass".
You can grab a list of the jobs I use here.
How do you manage student jobs in your classroom? We'd love to hear about it in the comments below.