Early in my career, I spent a lot of time reading unclear or obsolete documentation, poring over code, etc, when I could have asked the person sitting next to me and gotten an answer in 5 minutes. Sometimes, I didn't even know who the right person to ask was, but if I had just asked my tech lead, he would have been able to point me in the right direction.
Claiming that it reduces your overall time from several hours to < 5 minutes is maybe a bit exaggerated, since it also takes time to figure out what question you want to ask in the first place. But it's still worthwhile even if you end up investigating for 30 minutes instead of 3 hours.