A client of ours asked to look into their website, that was loading extremely slow. After trying to open the page – I’ve almost given up. Each page loaded for what seemed like a minute. And that’s on a laptop with fast wi-fi, phone and desktop computer with cable. Something was definitely wrong, so I sent an email to our senior developer to take a look.
It only took minutes to get the reply. Apparently, there was a script in the theme that blocked page rendering for about 20 sec. It took another few minutes for the site to load up almost instantly.
Pretty good for a 5 minute job! This was using some tools that we have to perform diagnostics on a website. Without them, and this is from experience — you may get sucked into changing your host, running multiple costly updates or even get told that your WordPress theme is out of date and you need a new site.