How long does your website take to load?
According to statistics on the HTTP Archive (an online resource for website performance and technology information), the since late 2010 the average page size for major web sites has grown from a generous 750KB, to an oversized 2.1MB!
Considering that in Australia our use of sites over mobile devices (using more costly mobile data) has more than tripled in that time (ref: ACMA), website developers need to ensure that we keep the page sizes down, or else we the risk losing our site visitors to faster-loading, less data-indulgent competitor websites.