general question

vir44

what is the importance of release/renewing ip addresses?

Danman32

If nothing has changed, and all is well, there is no importance.
It is important if the host (PC, IP based printer, etc) aquired an incorrect address or could not find a DHCP server to aquire an address as it was booting, it's IP lease expired and a DHCP server could not be found to renew, or configurations have changed and its existing IP address is no longer valid for the network. Thus releasing and renewing the address will immediately correct this condition if a DHCP server is now available. Otherwise you have to wait for timeouts and retries.