None of the jobs Ehrenreich encountered included health benefits, which is a huge issue for persons working in physically demanding jobs. When Ehrenreich returned to her "real life," she would have been able to see a physician or physical therapist, obtain prescriptions and pay for medications if needed, and in general address the aches and pains she experienced as a result of the work and past injuries. Her coworkers, on the other hand, had to continue to work regardless of illness, possible pregnancy, or any other conditions because they couldn't afford to not work and because they had no way to finance medical services.
The jobs came with varied amounts and types of training for the work to be done, but each of the employment situations turned out to involve substantially more work than Ehrenreich anticipated upon beginning each new situation. The extra demands in terms of labor and hours were never compensated with an increase in hourly wage.