>Plumbing work
Done some of that.
>electrical work
How often is this needed? Unless your house is so old and not up to code...? To give you an idea, I lived in a place for 2 decades and it never needed electrical work.
>trees that need trimming
It's your property - you control how many trees and how big. If it's too costly just get rid of them. Having said that, I just trimmed two trees on my property over a month ago. An hour or two of work and the right tool. Of course, if my trees were much bigger I'd have to pay someone.
BTW, I did not assume yard work as part of the amount per month. Of course, everything (including HOA, yard, etc) needs to be factored in, but I thought you were talking only about maintenance of the house.
>kitchen or bathroom remodels
How often? My house is almost 20 years old and I can see it going at least another 20 years before any such work is needed.
>painting
I assume you mean exterior? I guess - how much you need depends on the type of house. Mine uses vinyl sidings - no paint needed. But yes, you need to paint a few other parts. For my house, this is once every so many years - and the estimate I got was under $1000.
>replacing windows and doors
20 years old and look like new - I think mine will last another decade or two.
>furnace work including annual cleaning
I get my furnace tuned every year - costs $85. I included that in my estimate of less than $130/mo. Don't forget water heater maintenance too!
As I said, I'm not pulling numbers out of nowhere. I actually did this analysis some months ago. I have all the numbers on how much I've spent repairing stuff and maintenance in my software. I added it all up and calculated the number I gave you. It was actually $100/mo, but since then I think I've replaced two appliances so I bumped it up to $130 (total cost of the appliances + install is under $1000 - divide it up by 48 months I've lived there).