I notice when setting up remote debugging for the first time, that I have to enter my IP address

Here in Spain, internet service is really poor, and I need to reset my router every few hours.

Does that mean that I will need to change php.ini and reboot the server each time?

If your server that you want to debug is located in the public network and you want to protect it from being debugged by somebody else, you have to allow debugging only to youself. The most secure way to do this is to use ssh tunnel for debugging. In this case you need to allow localhost only.

Thank you Dmitry, I now realise that this is the way to go.

I am still working my way through the remote debugging setup, but your comment makes it worth continuing!

You can also allow access by host name. Even though your IP changes, the hostname assigned by ISP may remain the same.