This question has been hanging around in my head for a while; all the way from back in 2012, when we replaced our core network switch.
This switch was actually a stacked pair of old 3Com 4900sx, and it was responsible for layer 3 routing between VLANs in our network. We're just a two-man IT shop, where a lot of our internal expertise is more in workstation, server, and application support, with only basic network engineering, so we engaged a consulting firm for this project. The consultant's task was to look at how our network was configured, and what growth we were having, to make sure the new switch was set up well (not just matching what we had, but also looking to the future), as well as help with the cut-over to minimize downtime.
To make a long story short (too late), there were two noticeable configuration differences from the old to the new. The first difference is a much shorter ARP timeout. This makes sense to me; the rise of Wi-Fi means a device might move from one place to another and end up on a different port, invalidating cached ARP information. The second difference is the old switch used OSPF areas, but the new switch does not do any OSPF configuration at all. This part I do not understand. It's not so much that it doesn't make sense, as that I lack a frame of reference for knowing when or why one would want to use OSPF at all.
And so there is my question: when does it make sense to add OSPF to a network, or why would you choose OSPF over another option? I've been through several resources on this in the past, but never quite had this solved to my satisfaction.