One large docker file or two "small"

Hi everyone.
I’m working on a project, using R programming language, where I need a lot of packages for data preparation and modeling. The more packages I add the larger the docker file will be. Is there any “maximum” size of a dockerfile or can I without any trouble add any number of packages even though the final docker file will be quite large? Or should I create two docker file, one with packages for data preparation and one with packages for modelling?

Thanks.