Question About Real Time Preview

To answer your question, no.  Saving often is necessary for RTP to work. 

I 2nd Paul's and Jon's sentiments.  Real-Time Preview doesn't play nice with my local testing server, so I don't use it.  I use Open in Browser instead.  Save changes often with Ctrl/Cmd + S and refresh browser.

When I need to test on other devices, I use my local server's IP address which replaces any need for Device Preview on Adobe's servers.

RTP is a nice feature in theory, but in execution, it's flawed.

That flakeyness that Paul mentions, in concert with the fact that it requires a connection to Adobe's servers in order to function, stops me from trying to get it to work anymore.

Switching to Static Preview, what the old Preview in Browser has been renamed to, allows me to keep my work on my machine and not need to rely on Adobe's server up-time in order to do my work.

Real time preview is hit and  miss .... I would change the setting to 'default to static browser preview' in edit >preferences > real-time preview then just manually refresh the browser ... I've had more success using LiveReload along with the Firefox plugin