As long as you lock your bike up with something you’re doing better than 90% of people who get their bikes stolen. We hear the phrase “I just left it unlocked for a second and it was gone” with depressing regularity.
The other oft repeated mantra that drives us nuts is “There’s no point getting an expensive lock cos if someone wants to take it they will”. Don’t believe it. Buy a solid quality D-lock, secure your wheels, and be smart about where you leave your bike and for how long, and you won’t need to worry about it being stolen.