It really depends on the landlord, some our honest some our not.
In my 5 years in China, I’ve had good and bad landlords.
Living in a modern building helps.
Many modern complexes have handymen who can fix most basic day to day issues, from replacing lightbulbs (the ceilings can be quite high, or light fixtures can be difficult to remove), to minor electrical issues (sockets, light switches, frayed wires), to basic plumbing (clearing a blocked pipe).
The handyman may charge a small fee, but it usually less than 50 RMB.
If there are problems with equipment, like the microwave or fridge breaks, the landlord should replace those for you, unless you obviously broke them.
It is a good idea when you check out the apartment, you check and make sure everything works, and you can make a list of things for the landlord to fix, (it is far easier to get things replaced before you sign the contract).
It seems really tempting to try and save 500-1000 RMB a month and live in an old building, but based on my experience it just isn’t worth it.
Also, I think landlords have greater incentive to maintain modern apartments.
Like much of China, there are massive construction projects all over Kunming, new apartments are being built all over the city.
My guess is that landlords in old buildings are probably playing a long game waiting for their building to be tagged for demolition, so they can be compensated.
There is a pretty hard cap in what they can collect for rent, so there isn’t much incentive to spend money on an old apartment, that may be torn down in a few years.