I was wondering if it is better to use DHCP reservations for servers and computers that must have static IP address, excluding DHCP servers themselves, Domain Controllers, and DNS servers of course, by setting DHCP scopes for servers and setting for them extremely long DHCP leases?
The obvious benefit of using DHCP with IP address reservations instead of local static IP address configuration is that NTP setting, DNS servers, Default Gateway, DNS Domain Name, and all the other options provided by DHCP will be set in one centralized place, DHCP server options or DHCP Scope options.
A good example of this benefit is if a company IT system is undergoing reconfiguration, for example, new DNS servers, new NTP servers, all with different IP addresses, or new address for the Gateway. If you had hundreds or thousands of servers with statically configured IP address configuration, you would have to manually set all those settings on each server, possibly using scripts if NICs are named the in standardized way on all servers. I know this because I had to do I once.
Yes, it's better. That way, all configuration is managed in one place, and not spread out to individual servers. It makes reconfiguration a lot easier.
In addition; what components really need static IP's these days? Most can be handled by DNS updates.