I am close to buying 3 storage rooms in a good location near Zurich (Kilchberg/Rüschlikon). Intention is to rent them.

Do you think there is real demand for renting storage space in places like Kilchberg / Rüschlikon?
If YES: how much do they go for, monthly? (they are 11-15 m2).

Any experience / comments would be welcome.

In the middle of Zurich our office pays CHF 100.- p.m. for a 20m2 secured basement space.

If you're close to buying them, i would have thought it maybe sensible to find out about the market beforehand maybe......

It depends on exactly what is offered.
Can they also be used as hobby rooms?
Is electricity included?
Do they have windows/natural light?
Are there power sockets?
What floor are they on? Is there a lift?
Do they have sinks?
Do they have their own mailboxes and as such can also be used as a business address?
May seem odd points to consider, but I have seen all of the above facilities offered for rooms to rent labelled as 'storage rooms', which can ultimately be used for other purposes.

Electricity is included. Power sockets yes.
It has very good access (building quite new) & tenants can use visitor's parking.
One is same level of such parking, but has no windows.
The other is accessible with lift and has a small window (no direct sunlight).
No mailboxes / no sinks.

I did significant research already... and I am making it as extenensive as possible. ;-)

There is yet limited data you can get: little/no historical data on comparis (assumed is there is not much of storage space for rent in Rüschlikon)

ASSUME.....that is very risky for one who spouts such financial advice on a mortgage thread.