I'm used to working/consulting with small/home business people but I might have a change to stretch a little and work for a friend on a bigger network install. His building is going to have three or four different entities in it that are all his but need to be protected from one another from a networking perspective. Instead of installing separate physical networks (because the spaces may be repurposed in the future) I was considering one physical network, then dividing things up with VLANs. I know how they work in theory but I've never actually built them. Anyone have any experiences with them they would like to share? Always use/avoid (vendor), make sure you always/never (insert advice here), they make life a breeze/nightmare, stuff like that? Thanks in advance.