Utilities can use you up
Utilities can be a major issue for landlords if not set up properly. If you supply utilities to your tenants, you are generally not permitted to terminate these for nonpayment or other issues, and penalties can be severe.
Want to keep the bills in your name but have the tenants pay their portion to you? The law does not generally allow you to collect if they default on these sums, so you may risk losing out if the tenant stops paying their portion of the utility. Plus, you are still required to furnish them with these utilities, even if they fail to pay. Unless you can incorporate a flat fee into the monthly rent figure which covers your expenses even as costs continue to rise, it is best to insist that tenants pay utilities directly, under their own names. Then, in the event of default, you are not responsible.
This means that properties containing two or more rental units need to have split utilities; separate furnace, hot water heater, meters, etc. It is much easier and cheaper to purchase an already-split property than to try to do this yourself, so this is an important factor when you are looking at multiple-unit properties. Duplicate systems will mean more maintenance costs over time, however.