Federico Viticci, at MacStories, talks about having a reliable, trusted system for getting your work done. If there is one extensive article you read today, make sure it is this one.
For me, the trusted system has become a synonym of great software developed by people that are serious about the bits and Xcodes they work with. Software from people that have something to lose if things go south. Apps from developers that are deeply invested in the platform — apps from people that often do this for a living but that are also users of their own creations. And this synonym has led me to trust the smaller, indie devs less, because I always fear the app I’m showing interest in will be discontinued tomorrow and never come back to support my needs.
I can vouch for being burned by some devs who took my money, and other people's money, and then promptly left their app to rot or removed it from the store entirely. Granted, this happened early on in the App Store, it was a new market, but I am also more cautious now. I've developed relationships with some developers, like the folks at the Iconfactory. I trust AgileBits with my most secure credentials. I could go on.
Even more so, I have become very hesitant to adding new items to my trusted system. I agonize over mucking with my home screen layout because it means retraining muscle memory. But that doesn't mean I won't go search for something new if the need arises. However, I read many reviews and weigh the usefulness of an app heavily before trusting it by clicking the buy button.