In the UK, it used to be that you got a new IP address every time you logged on to the internet. You had to pay double or more to get a static one.
Now pretty much everyone has a static one, except when they are using hotspots and whatnot.
I switched my provider to one that provided free static IP addresses about 8 years ago. About 4 years ago, static became the standard. I don't know of any that offer dynamic still.
Dial up modems resulted in new ip addresses with every connection.
The one advantage of having a static ip address is if you want to use your own computer as a server. When you do that, you could hypothetically keep a server with top secret confidential emails on it in your basement, and if you ever got in trouble just delete them, and since they are not on a remote server, you are safe.
Frankly, having a server in one's own house is silly. It ties up a computer, is prone to crashing, and eats up your bandwidth. There are many remote hosting services which are dirt cheap.
IPv4 has a LOT of ip addresses, so they don't need to be re-used much.
IPv6 has so many ip addresses that they would never run out of them.. and each address is permanently assigned to a specific location - hello Big Brother.
What gets me with Facebook is that they want it both ways. They both demand to know exactly who you are and where you are by your ip address and email address.. yet at the same time they demand more for advertising purposes such as your cell phone number and everything else. Here's an idea.. when you set up an account.. give them your PHYSICAL address.. then they can SEND you via snail mail a verification letter.
Facebook doesn't fool me.. they are crooks.