I live in the Netherlands, where kids under 25 rarely own a car, and everyone goes everywhere by bike... I've only had my bike stolen once and it could've been avoided, my mum forgot to lock it. If you buy a proper lock it won't get stolen. Locks can get pretty expensive but they're worth it if it means you can keep your bike. Mine had a rrp of E30.
Stealing prevention tips!
* It's important to always attach your bike to something that cannot be moved and is pretty solid itself. There's no use in attaching your bike to a fence when it's really easy to break the fence itself.
* A bike thief usually uses a bolt cutter to quickly break the lock, then carry the bike into a van and take it home where they'll have more equipment. Thus, the only thing that really matters is how and where you attach your lock. Make sure to always attach the lock more than 3 feet above the ground. When the chain is dangling to the ground, the thief can put the bolt cutter on the ground and use his body weight and it'll be easy to break even a very solid chain. When he can't use his body weight to lean on the bolt cutter, it'll be much harder or even impossible to break proper locks.
* A proper chainlock is hardsteel. It doesn't matter if the chain links are really big or not (because they might look solid but could be weak on the inside) it only matters if they're hardsteel or not. The University of Delft did a test some years ago, they tried to break hardsteel chainlocks with a bolt cutter. They used a 60 cm boltcutter, the size preferred by thieves because you can hide it under your coat or in a backpack, and one with the best quality of blades available. An average person could create a power of 10,9 kiloNewton with this type of boltcutter (while not leaning on it). So, if you want a good lock, you need one that can resist a power of 10,9 kN. On this website you can find a list of all brands that passed the test: http://www.fietsersbond.nl/urlsearchres ... number=804 The website itself is in Dutch but most of these brands are sold worldwide.
* It helps to put your bike somewhere where a lot of people are waiting, like a bus stop. These people are bored and stare around. It's the other way round at a place where a lot of people are only passing by, because they don't pay attention to their surroundings.
* I always try to find a secured bike park for my bike. I don't know if they have these in other countries, but in here we have a secured car parks, but just for bikes. I really like those as they aren't expensive and you don't really have to lock your bike. It really is worth the money. I used to have a subscription to the park in my uni town and it cost me only E11 a month.