When training a relatively small DL model, which takes several hours to train, I typically start with some starting points from literature and then use a trial-and-error or grid-search approach to fine-tune the values of the hyper-parameters, in order to prevent overfitting and achieve sufficient performance.
However, it is not uncommon for large models to have training time measured in days or weeks [1], [2], [3].
How are hyperparameters determined in such cases?