question: Save checkpoints without overwrite
context: Hi there,
  I am using the ModelCheckpoint callback to save my model every n epochs but I cannot find a way to prevent PL from overwriting/deleting the previous checkpoint.
  Ideally, I would like to keep the default naming convention {epoch}-{step} but without losing previous checkpoints.
  Thanks
answer: you can create a custom ModelCheckpoint instance with save_top_k=-1 and pass it in inside Trainer callbacks.
  ckpt_callback = ModelCheckpoint(save_top_k=-1, ...)
  trainer = Trainer(callbacks=[ckpt_callback], ...)