How often do you have to replace a router? I personally think it’s a really bad approach to set static IP on the devices — the IP may not be compatible with your router’s IP range (especially if you change your router, the IP range may not match at all), or you may accidentally configure two devices to have the same IP causing an IP conflict. The reason routers have this DHCP reservation feature is exactly to address such issues. You are essentially trying to manually recreate what routers can do automatically.