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!
It is possible to connect two devices with a single fiber at one end and multimode at the other. In log run, it is always helpful using a combination of single mode and multimode cables which will save on costs and excessive wiring as you are planning to extend your network. So don't worry about using single mode converters as it will save your expenditure in long run
Single mode fiber costs have dropped a lot in the last few years making it more appealing for a lot of people. I do agree that you can be smart about combining multi-mode and single-mode fibers to save money. However, In the automation world, I am strongly against fiber converters & adapters. in the IT world, the system is designed to continuously monitor traffic and failover between cables/switch ports. However, in the automation world, we focus on PLC hardware and the Turbines/machines that we are operating. Converters & adapters add another failure mode into the system that Automation does not track.

I see a lot of power plants migrating to Single mode fiber systems. Single mode has less noise loss so, in my opinion, a less chance for failure in the future. However, one thing to keep in mind are the devices you are connecting. PLCS/Automation systems are just starting to come out with fiber connectors imbedded in them. So make sure that they have the capability to do Single mode.