What you always need to understand is your safety is of the utmost concern. This is especially true when you are rock climbing. So, that begs the question of when you should be clipping your carabiners.
First and foremost, you should always ensure that you are balanced and that your other hand has a secure hold. From there, you should try to clip to a bolt that is a moderate reaching distance away. The last thing you should do is make a long reach for a pin (as this will also add unnecessary slack).