This is a fairly basic guide which should help admins discover some of the biggest client performance problems which I discovered in Community Feedback when casually flipping through sites.
Firstly, you probably want to go to your site, and then right-click, select Inspect (or Inspect Element or whatever variation your browser likes) and that will open a little window (or pane). After that, go to the Network tab and do a hard refresh (CTRL+R on most browsers and something weird on Firefox).
You will now see a lot of data poring in about the requests the page is making, what protocol they're using, how much data they're using up and how much time they're taking. If the first one which is usually the name of the page is particularly slow, then it's usually a problem with the software you're using for the site.
If you see a ridiculous number of requests, on the order of a hundred or more, even fifty would be a red flag to me, then you might want to look deeper. Sometimes, you will see a lot of gunk you don't actually need or the same thing being fired over and over when it shouldn't.
You will also want to keep an eye on how much data is being transferred, as data costs some serious money on mobile and it meaninglessly slow down page loads, particularly for users who are located geographically far from the server.
And of course, you will naturally want to look at how long it takes the page to load, for instance, you ideally want it to be completely done within a second or two (and even that may be pushing it, it's said that a mere hundred millisecond difference between two times can mean 10% of your users!).
You will also want to keep in mind a fair bit of the data will be cached, in other words, it will be stored locally on the user's machine for a short time to avoid firing off the same requests every now, however you can't necessarily rely on this, particularly the first time someone arrives at your site when they'll be most prone to leaving on the spot.
The protocol is also important. HTTP/2 is far more efficient at transferring large numbers of files, particularly tiny ones than HTTP/1.1 and there is even HTTP/3 which can help reduce the number of round-trips on mobile to make things load even faster.
Finally, https://www.webpagetest.org is your friend when it comes to digging up additional data on your site and it sometimes gives you some nice suggestions on what you can optimise to get faster!
Firstly, you probably want to go to your site, and then right-click, select Inspect (or Inspect Element or whatever variation your browser likes) and that will open a little window (or pane). After that, go to the Network tab and do a hard refresh (CTRL+R on most browsers and something weird on Firefox).
You will now see a lot of data poring in about the requests the page is making, what protocol they're using, how much data they're using up and how much time they're taking. If the first one which is usually the name of the page is particularly slow, then it's usually a problem with the software you're using for the site.
If you see a ridiculous number of requests, on the order of a hundred or more, even fifty would be a red flag to me, then you might want to look deeper. Sometimes, you will see a lot of gunk you don't actually need or the same thing being fired over and over when it shouldn't.
You will also want to keep an eye on how much data is being transferred, as data costs some serious money on mobile and it meaninglessly slow down page loads, particularly for users who are located geographically far from the server.
And of course, you will naturally want to look at how long it takes the page to load, for instance, you ideally want it to be completely done within a second or two (and even that may be pushing it, it's said that a mere hundred millisecond difference between two times can mean 10% of your users!).
You will also want to keep in mind a fair bit of the data will be cached, in other words, it will be stored locally on the user's machine for a short time to avoid firing off the same requests every now, however you can't necessarily rely on this, particularly the first time someone arrives at your site when they'll be most prone to leaving on the spot.
The protocol is also important. HTTP/2 is far more efficient at transferring large numbers of files, particularly tiny ones than HTTP/1.1 and there is even HTTP/3 which can help reduce the number of round-trips on mobile to make things load even faster.
Finally, https://www.webpagetest.org is your friend when it comes to digging up additional data on your site and it sometimes gives you some nice suggestions on what you can optimise to get faster!
