They are the sort of tenants landlords dream of.
Seldom moving out and always paying the rent on time.
No broken windows or soiled bathrooms.
I was taken around one such place on a visit to the Netherlands a week ago.
But these tenants are fussy about two things: tip-top air-conditioning and electricity supply.
That means absolutely no outages, which explains the standby generators and the rooms of batteries designed to take over should the regular supply fail.
Even the diesel for the generators is tested every month to make sure they will work when needed.
The other requirement is maximum security. No one enters or leaves without stringent biometric checks.
Welcome to the world of Internet data centres without which the World Wide Web and the 24/7 digital world would not have been possible.
We take all of this for granted, but have you ever wondered how it is that Facebook or Google or your Internet banking is available all the time?
Where do these companies store their computers with all the data that's being generated by millions of users and how do they keep them running so reliably and securely all the time?
The answer was in front of me in this facility next to Schipol airport in Amsterdam run by Dutch company Interxion.
There are many such centres all over the world, including in Singapore, but the Netherlands wants to be the digital gateway to Europe, and I am visiting to find out how it is going about fulfilling that ambition.
Google is their prized catch and has announced the building of one such data centre in the Dutch province of Groningen in 2016, an investment of 600 million euros (S$980 million). It will require electricity enough to power 400,000 households.
Why is the Netherlands so keen on developing this business which consumes so much energy and uses so much space?
For starters, it's a natural choice since 11 out of the 15 Internet undersea cables across the Atlantic from the United States to Europe go through Amsterdam which houses the world's largest Internet exchange.
The country is host to some of the top names in the business: Google, Microsoft, Cisco, Infosys and Huawei.
With its extensive broadband network, 90 per cent of the people pay their taxes online, 70 per cent do Internet banking.
Within a 300km radius of Amsterdam live 200 million of some of the wealthiest and most advanced people in Northern Europe, giving it one of the most enviable high- income markets.
The Dutch government believes in the digital world's future, and has invested heavily in both the infrastructure and the training of its people.