Evening and part-time openings around Phoenix - 9 months and counting

I am looking for part-time work that fits around school hours and found a few evening shifts near Phoenix. There are 12 people counting on me, so I am trying to be careful. Shifts are four to six hours and the pay is weekly. Is the schedule really fixed?

I worked evenings at a hotel. The hours were steady and the team was friendly, but weekends were busy.