It depends on the physical network layout as well. As soon as you have an area with several clients that should be in different networks but all of them are supplied locally by a single shared switch, you would have to use VLANs or redesign your physical network. With VLANs you create distinct virtual networks over a shared physical network. Means: one ethernet cable with 2+ isolated networks on it. For physically seperated networks you'd need seperate cables for each network required at the target location.
I wouldn't mention this but as you are talking about a "home network", I'm not sure if you could actually go for seperate interfaces without rewiring the whole network...
In general I would always prefer physical networks over virtual ones if possible.