Properties tend to get annual or semi-annual inspections. From the landlord's perspective this is something of a safety mechanism. You get to fix the cupboard door that's loose, or leaking tap, before the whole unit has fallen apart of building been flooded. That kind of thing
In theory, that is how it should work - some landlords are quite happy to work that way, but some are just negligent and greedy too.
Many London landlords didn't even check the contracts with their agents, let alone checking the property
. E.g. many agents tell the landlord `we take 10% of the rent', and in the small print, it says they can take 10% for 1 year out of the first rent payment. In other words, the landlord gets 0% of the first rent payment. If the tenant disappears in month three, the agent keeps the fees for 1 year anyway.
Here's a scenario. I rented a room to a couple of girls from Vaucluse in Sydney. Lovely girls it seemed. But within three days it was clear there was a serious problem. They were major smack-heads. I had them out within c.10 days, and just had to clean up all the blood and vomit that they left behind. Now if I had let them a private apartment of their own, those two would have been hard at it for heavens knows how long before I found out about it...
A newspaper ran a list of the worst tenants once (a) the guy who ripped up floorboards so a room could become a stable for his horse and (b) the tenant who took a sledge hammer and knocked out a wall to make an `open plan' kitchen dining area.
Every time a landlord does a rent increase, he risks changing his tenant for one of those lunatics.
As many people have said, the practices in Singapore are ridiculous, the rent increase demands are not `market rents', they are just bullies and speculators trying their luck. To calculate a true `market' rent, you'd need to have a transparent way of reporting actual prices and vacancy rates.
Think of it this way:
(a) landlord has 1 flat and two tenants, one tenant offers $5k/month and the other $3k/month, so the market rent is $5k/month
(b) landlord has two flats (identical), each has a mortgage at $2k/month, two tenants come along, one agrees to pay $5k/month and the other $3k/month. There are no other tenants in sight, so the landlord takes them both at their offer prices. Which is the market price? $3-4k/month