A site that feels quick on office wifi can be unusable on BART or in the shadow of a downtown tower.
Where people actually open your site
Underground on BART. In a garage below a Victorian. On a downtown sidewalk where the buildings kill the signal completely.
That is the environment the page is actually judged in, and it is nothing like the one you built it in. Eight seconds down there hands the job to whoever managed two.
What a page builder actually ships
A builder loads the machinery for every layout anyone might assemble. Your five-page site pulls a framework, a grid system, an animation library, an icon set, and a stylesheet for features you never used.
None of it is removed when you finish. It ships to every visitor on every page forever.
Photos straight off the phone
A phone photo is 4 to 8 MB. Ten on a gallery page is 50 MB the visitor downloads to see your work.
Resized properly the same ten come in around 400 KB and look identical. Biggest single speed win on most small-business sites.
Widgets somebody sold you
Chat bubbles, review carousels, popups, booking embeds, tracking pixels, a cookie banner. Each loads code from another server and your page cannot finish until they answer.
On bad signal they fail one at a time while the customer watches an empty box. Most earn less than they cost.
Fonts that hide the text
A page pulling four font files often hides its own text until they arrive. The customer sees a blank page indistinguishable from a broken one.
Two weights, from your own domain, text visible while they load. Nobody chose a contractor over a typeface.
Test it the way customers use it
Turn wifi off, ride a stop on BART, and open your own site. That is the test that matters, not a score out of 100.
If you cannot read the first line and find the phone number in about three seconds, it needs work.