Some ISPs made sure to allocate rather a lot of addresses around 2010, and have room to grow by allocating more efficiently. The ISP where my colo hosts lives used one /30 per customer at the time (which is a fine, sensible strategy, just not one that saves IP addresses). When one of those old customers leaves, the ISP can use the /30 for four new customers.
Another ISP I deal with has already run out of v4 addresses, and some of its customers only have CG-NAT access to IPv4 today. That ISP already has to optimize many things for low v4 address usage.
Carrier grade NAT is a nightmare that ISP's will start going down from now. It will be offered as a cheaper option but in fact it breaks how the Internet was designed to work. Think about your external IP being a 10.x.x.x address and you sharing a public address with 100,000 other subscribers. Thinking about how P2P connections like video conferencing would work.
Push for your servers to have IPv6 by default, push for IPv6 at your work place, push for your DNS provider to support IPv6. Always ask any service providers their IPv6 status.
Some ISPs made sure to allocate rather a lot of addresses around 2010, and have room to grow by allocating more efficiently. The ISP where my colo hosts lives used one /30 per customer at the time (which is a fine, sensible strategy, just not one that saves IP addresses). When one of those old customers leaves, the ISP can use the /30 for four new customers.
Another ISP I deal with has already run out of v4 addresses, and some of its customers only have CG-NAT access to IPv4 today. That ISP already has to optimize many things for low v4 address usage.