I moved my hosting to Netlify after learning about their git-based workflow support (also because free!) This meant I could remove the custom git-hook-based setup I had implemented on my previous host: commit. I also took the time to remove the bash-script post-processing I was doing (e.g. gzipping files). I used Netlify services to replace much of the asset optimization and post-processing since they offered asset concatenation, minification, and finger-printing. I also added in jekyll-assets to provide some tools within jekyll to handle assets. For example, adding image dimensions to the generated html, something I was able to contribute to jekyll-assets: pull request.
Some performance optimizations remained manual however. Such as svg/png/jpeg optimization including making jpegs progressive and generating responsive image sizes. I learned a lot from working on those image optimizations using tools such as optipng, svgo, jpegtran, and of course imagemagick.