Hi there, I’m new here 
I already installed HomeAssistant on a Raspy5 and I’m considering installing other accessory services (like for ex. the Mosquitto broker with Zigbee2MQTT) on another Raspberry Pi on the same LAN.
What’s the general experience regarding such a setup?
Would you suggest the scenario? Pros and cons?
Check to see whether there are add-ons first. There is certainly a Mosquitto broker.
I know it’s there, I’m already using it in the current setup and it works fine. That’s not an issue.
My intent is to run some services independently on other Raspis as I’m already doing with PiVPN and intend to do with other stuff which at the moment are not directly related to HA itself.
My question is more related to the feasability and opportunity of such an approach with services that for a standard setup seem at first glance to have to be integrated in a single HomeAssistant unit.
Why though? Unless the devices can work without HA that’s pretty much the only reason to have something on another device. Incase one goes down some functionality exists.
Nothing wrong with stacking services on a single device. Idle cycles are wasted cycles.
Spread out things that are mission critical like DNS. For home use its just not necessary to spread out that much.