Using annual and quarterly labor market data from the US and France, we study the relationship between the extensive and intensive margins of labor adjustment, job polarization and non-standard work along the business cycle. We derive four stylized facts. First, changes in aggregate hours are mainly driven by fluctuations in per-capita employment rather than hours worked per worker. Second, recessionary drops observed in aggregate hours are, to a large extent, due to the disappearance of routine work. In the US, the fall in routine standard employment accounts for most of the decline in aggregate hours, whereas in France, routine jobs losses in both standard and non-standard work matter. Third, the dynamics of routine standard employment are driven by flows from and into unemployment in both countries. Fourth, the dynamics of routine non-standard work differ across countries. In the US, fluctuations in routine non-standard employment is driven by inflows from routine standard work, while, in France, changes in routine non-standard work are accounted for by ins and outs from unemployment. Our findings support the view that within-employment reallocation, through the use of non-standard work, is an alternative margin of adjustment in the US. This is not the case in France and flexibility is achieved by adjusting hiring and separations of standard and non-standard work. In bad times, reduced stepping stones contribute to the fall in routine standard employment.