Single Mode vs Multi Mode for Fiber Optics

I have a lot of fiber optic runs where I work for process network extensions, and they are all multi mode. I’ve been told that single mode is the way to go now, but that was by our corporate IT people. I have been dong some research, and it seems that the only drawback to single mode is the cost. I have some new fiber runs to have installed soon and wanted to get some opinions on the subject. I would prefer to stick with multimode, because that's what we have now, and I don't want a bunch of SM to MM converters to link the old runs to the new ones. Anyone have any insight?

Thank You
Single mode is for high transmission rates over long distance. Basically backbone tunnels for large nationwide networks. Unless you network spans huge distances, multimode is fine.
It does come down to distance and price, but don't forget that the distance is dependent on bandwidth. With the faster gigabit speeds in use today, the multi-mode distances have shrunk. That is probably why your IT department has moved to single-mode only. Most new equipment connects at 1 Gbit so run the requisite distance calculations before choosing!