Your customers search the web on mobile. Is your website mobile first?
When you open a website in Google Chrome, you can test the site's speed index against Google's own metrics. Here's an article explaining how to open Google's auditing tools in Chrome if you want to try this yourself.
Websites are graded on a scale of 0% to 100%. A perfect score is almost impossible on a modern business website.
A score of 90% or better will CRUSH your competition in speed indexing.
Take a look for yourself: