Thank you…
So for example …why can’t HA run only on a pc instead of NUC?
You can. We tend to use NUC’s for their nice low power consumption and small form factor. You can use a PC if you want. The other factor is that there is a Home Assistant image available specifically for a NUC.
PC performance depends on memory, cpu, gpu, and other factor.
A server is no more than a computer that is generally used headless(without monitor, keyboard, mouse).
A NAS is a term for server with a lot of storage attached. The storage is useful if you have lots of movies, music and want to have them available/playable by your devices
NUC is a specific model of PC. It is small, compact and have powerful cpu. Memory, cpu etc is upgradable but has limit here. Costs start at $200USD.
Raspberry Pi is another form-factor computer. It has several model versions, latest being Rasberry Pi 4. This has set memory and cpu and cannot upgrade unless buy newer better model. Cost are around $20 - $80USD.
Others recommended other model computers; rack mountable, desktop. The performance and cost if these may vary greatly.
In the end all these are computers. Which one to get greatly depends on needs. A Raspberry Pi makes great server and may be setup to function as NAS by using usb drives. A NUC is great server but make good NAS or desktop.
If you have old desktop or laptop. You can just use those.
I use an old i7 laptop with ubuntu
We currently use a MacBook Air at home which is about 9 years old. We’re buying a new one very soon. Maybe I can use the old MacBook dedicated only to HA???
Uh oh…lol. jk. So bought the Ras PI 4. Thanks for the advice everyone. I think this is the best way to start.