It means long stressful hours to meet your billable hour requirements. Not only will you need to work 60+ hours per week, but you'll need to bring in new business to the firm. Once they evaluate your partnership compatibility, you'll be a slave to the firm. Granted, the money is usually good and that probably means you can retire early. Nonetheless, you don't want to let yourself go physically and/or let your family life slip. It's not an easy path and many classmates I know went in-house within 3 years of going to BigLaw.