Answer:
Use DHCP (which stands for Dynamic Host Configuration Protocol)
Step-by-step explanation:
This is a common problem, using DHCP is debated amongst the IT world that it could serve as a petri dish for hackers to invade but realistically, the pros definitely outweigh the cons. But if you want to booster shot your security, you can always assign IP addresses to MAC addresses at your DHCP server but manually. Don't forget to backup the DHCP server multiple times are day.
You could also adopt the usage of using shorter DHCP default lease times. As well try to enable the IP address conflict detection in the DHCP server.