@AndreaSottana thank you for the explanation. I am using EfficientNet-B0 for a 4-class classification problem. I am trying to replicate a paper, they have stated 'we used the input size of 224×224pixels, train the model at a learning rate of  0.001  and  decrease  with  a  factor  of  0.1  if  the  validation score  does  not  decrease  after  5  epochs.’ So, in this context should I go for scheduler after one epoch?