OSPF

[Senbonzakura]

Alright so I have a question regarding OSPF and areas.

In this example, we have all switches running on L3 and they're handling the routing and they're all meraki.
I have a main site which has stacked switches then we have direct trunk links going to the 6 other sites so imagine this as one giant star topology of switches.

With OSPF would I want all the off-sites to be there own area or would I make them the same area as the main site. It's weird how the topology is setup but the other sites aren't accessed through the WAN at all.

If they all have to be there own area IDs, what would be the different between making all apart of the same area ID compared to having different ones?

[MHM Cisco World]

if you use SVI as Peer OSPF, then you must use one area in all SW. 
you can not use area x for SVI of vlan1  in SW1 and use area y for SVI of VLAN1 in SW2
this broadcast. 
if you use router-port or SVI for each connect between SW then you can use different area. 

[Senbonzakura]

So for example if lets say the off-site switch interface for the VLAN lets say is 50 10.0.50.1 and at the main site it's 50.0.50.2 we can use different areas?

VLAN 1 isn't used anywhere since that was purged out.

[MHM Cisco World · Accepted solution]

note:- I mention VLAN1 as example it can any VLAN. 

now this simple lab 

IOU1 have in vlan1 with ip 10.0.0.1 
IOU2 have in vlan1 with ip 10.0.0.2 

I config IOU1 as area 0 
I config IOU2 as area 1

you can see ospf log message show that area mismatch. 

so since you use SVI of VLAN connect two SW then you must use same area.