My personal feeling is that for a standalone/SFH dwelling, the bare minimum is about $2k a year to cover all mechanical systems, roof/siding/paint/landscaping, etc. That's assuming a very small house in basically good shape with nothing weird.
Every property is going to vary, though. You could have a cinderblock place with a metal roof and all electric appliances/no washer or dryer and it could cost less. You could have a 1890 place with a sinking stone foundation and lead paint/asbestos, clay pipes, and shake and longstanding deferred maintenance and it could be a lot more to the point where it makes more sense to tear it down than keep maintaining it.
The 1% for maintenance thing makes zero sense unless you have a totally median home in a totally median location, and even then it's probably not that accurate.
Low end rentals get *killed* by maintenance, management (property managers are going to charge some kind of minimum around $100 a month even if your rent is only $650, unless they're managing a LOT of rentals for you, because low rent does not correlate with low hassle tenants), and tax overhead.
-W