Webpage Cache Control Strategy

I've never come across any solution that works 100%.

Assuming it is an Apache server, something like this in .htaccess file should do the trick, it will stop caching. If you are not sure what a htaccess file is, ask your web host for support...

# DISABLE CACHING
<IfModule mod_headers.c>
    Header set Cache-Control "no-cache, no-store, must-revalidate"
    Header set Pragma "no-cache"
    Header set Expires 0
</IfModule>
    <IfModule mod_expires.c>
        ExpiresActive Off
    </IfModule>
    <IfModule mod_headers.c>
        FileETag None
        Header unset ETag
        Header unset Pragma
        Header unset Cache-Control
        Header unset Last-Modified
        Header set Pragma "no-cache"
        Header set Cache-Control "max-age=0, no-cache, no-store, must-revalidate"
        Header set Expires "Thu, 1 Jan 1970 00:00:00 GMT"
    </IfModule>

As it hasn't been asked, is this a site you have built yourself or is this a site that you are building using a CMS like Wordpress?  Depending on whether you have access to the code, you may opt for the options below or if you are using a CMS, we could offer recommendations for a plugin that could help with forcing your cache to be updated. For instance if you are using Wordpress, I would recommend WP Rocket.

Do you have caching expressed in your HTACCESS file?

An example for a site that's updated monthly.

## EXPIRES CACHING ##
<IfModule mod_expires.c>
ExpiresActive On
ExpiresByType image/svg+xml "access 1 year"
ExpiresByType image/jpg "access 1 year"
ExpiresByType image/jpeg "access 1 year"
ExpiresByType image/gif "access 1 year"
ExpiresByType image/png "access 1 year"

ExpiresByType image/x-icon "access 1 year"

ExpiresByType text/css "access 1 month"
ExpiresByType application/pdf "access 1 month"
ExpiresByType text/x-javascript "access 1 month"
ExpiresByType text/javascript "access 1 month"
ExpiresDefault "access 2 days"
</IfModule>
## EXPIRES CACHING ##

This article may be of assistance

https://medium.com/@codebyamir/a-web-developers-guide-to-browser-caching-cc41f3b73e7c

This shows that the main document is always retrieved from the server while supporting files will be retrived from the browser cacche.

I'm afraid you cannot force people to do something they refuse to do.  Just ask the un-masked, un-vaxed COVID-19 patients who are surging the new outbreaks right now.  No matter what you tell them they should do, people do what they want to do.

OPTION 1:

Add a notice to the top of time sensitive pages and hope for the best.

Refresh:

• Windows and Linux browsers: CTRL + F5
• Apple Safari: SHIFT + Reload toolbar button
• Chrome and Firefox for Mac: CMD + SHIFT + R

OPTION 2:

If you're willing to compromise on page performance, add Pragma no-cache and expiration date meta tags to your document <head>.  And hope the end user's browser doesn't ignore it.  BTW Expires is in GMT date & time.

<meta http-equiv="pragma" content="no-cache">

<meta http-equiv="expires" content="dd Mon yy hh:mm:ss">

<meta http-equiv="cache-control" content="no-cache">

Good luck!