Total expenses = $1150/month (am I missing anything?)
Insurance, vacant months/tenant fails to pay months, minor touchups between tenants ($500/year; paint, clean carpets, vaccuming dryer vent ducts (fire hazard), etc.), big repairs (new appliances, chipped/stained counters, broken bathroom sink, etc.) every 15 years ($500/year), major renovation every 30 years ($40k in 2015 dollars, or ~$1250/year).
Also, don't forget to bill yourself for your own time. It's not ROI if you're working; it's an hourly rate. Give yourself at least minimum wage if you enjoy the work, and double or triple that if you don't. Work includes meeting time with your management company, doing paperwork/taxes, and other really simple stuff that you wouldn't otherwise be doing. This is strictly an accounting thing to ensure your investment is the best use for your money; you don't need to cut yourself a cheque.
The maintenance requirements vary a bit depending on the type of tenant you expect. Low-rent tenants have lower expectations; high-rent tenants have much higher expectations for maintenance. Your goal is to ensure you never have to charge less rent than the neighbourhood supports.
Both require proactive maintenance for anything involving water. If a tap breaks and floods something while the tenant is away it's your problem, not theirs.
