Rules for fixed IP

In my network I've hookup up multiple devices which I think is handy or even necessary to provide with a fixed IP address, like a Rasperry Pi, a wired AP, NAS, an OpenTherm monitor, my central heating system and some consoles with port forwarding enabled.

A fixed IP address can be forced upon a device from the DHCP server/router (static leases) or it can be configured in the device itself (static address).

Maybe this is a stupid question but are there any rules/policies on how and when to provide a device with a fixed IP address and which method to use?

My rules of thumb re: ip fixed/dynamic.
If I may need to access the device when the network is partially out of service (ie dhcp server broken) or if it's fixed equipment like a router/switch/server then it's a static IP configured in the device.
If it's a semi permanent piece of equipment like a camera or test server then I'm more likely to give it a static Ip but configured via the dhcp server and the device MAC address.
If it's a laptop/desktop/mobile phone (ie a device a 'client' device) then I just use a dynamic dhcp address.

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In a home network, static leases are the best of both worlds: you don't have to go through the hassle of setting up IP and DNS addresses etc on each client (which is very inconvenient for portable devices, particularly laptops, and you get a "fixed" IP that you can use to accesses the different devices.

Also using static leases let you see all IPs conveniently in one place and avoid accidentally having duplicate IPs.

The only good reason I could think of for using static IP is when you have a device that's more "fixed" than the router (e.g. server) that you need to make sure its IP isn't touched even if you swap the router, in that case I would give it a static IP outside DHCP range, and keep the rest of the devices as static leases.

That's more or less the approach i took (without knowing why).
The really (more or less) fixed components of the network (like AP, RPi and printer) I gave a fixed IP (outside DHCP range). All the other stuff (like NAS) a static lease (also outside DHCP range).

Only exception are the devices who need port forwarding. These have a static lease with an IP in the DHCP range (i don't know why i did this but seemed appropriate).

So I geuss no golden rules for this but common sense.

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