Caching is a good help, but not the only thing you can do. Caching is what we all should do, for all websites where possible. It is part of the optimisation of the performance of a website at the end of the development process.  But real optimisation of a web project should start at the beginning with critical assessment of design elements, like images. Do we really need that large (stock) photo, do we really need a bloated framework, etc. Moreover, browser caching only works on the second and adjacent page loads. The largest impact on the visitor is the first visit: that is where you make the first impression.