Again it depends on the time and place and laws, for example early medieval peasants in Poland worked for their lords around 10-20 days per year, which increased to 100-150 in late medieval (king peasants usually had it better than church peasants and private noble peasants had worst), but XVIII century serfs were worked to the bone to the levels that foreign noble travellers were shocked with the inhuman treatment serfs recieved.

For added detail, vegetation season in Europe is around 180-220 days, not to mention tyranny of weather knows no compromise, so there were cases where peasants literally died because they were forced to work for their lord and missed for example optimal sowing season.