Recently I was quite positively surprised when I noticed that the apps I bought in the Ovi store are not locked to a certain device but are part of my account in the Ovi store. In other words, when I changed my device I could install the apps again free of charge on my new device. That's good to know since I tend to change devices quite often so I'm quite happy that my apps will follow me to a new device. Makes a lot of sense from a user point of view!
How about the behavior of other app stores, do they allow to do the same?
Yes; Apple app store allows you to install the apps for free on multiple devices, as long as you use the same iTunes account.
What’s more, you can have apps installed using more than one account on one device – quite useful when you want your whole family to have some app; you need to pay just once.
Android, too.