Skill time
Some skill checks are instantaneous. That is, used during combat, they cost no Action Points (The Combat chapter gives a brief overview of how to use AP in combat). Some skills are used as part of another action in combat. Some skills have AP costs inherently. A few can take days or weeks. Each skill entry may detail the amount of time, if any, the skill takes to use.
Take 5
On skill checks that carry no penalties for failure (see the Retries portion of a skill description) and your character is in no immediate danger, you can choose to take 5 instead of rolling. This takes no additional time than a skill check with a roll. You can save some time around the gaming table by skipping the dice roll and just assuming the median of 5.
Take the Best
On skill checks that carry no penalties for failure and your character is in no immediate danger, you can choose to take 10 as if you had rolled it. (This does not count as a critical). As opposed to "Taking 5", taking the best requires far more time. In game terms, your character keeps trying until the check is done perfectly. Usually, this means taking the time it might normally take for one attempt and multiplying by 10 or more.
For example, Bryan's character Phineas needs to hide in a warehouse so he can eavesdrop on a conversation that will take place in an hour. His bonus to this check including his attribute and skill ranks is +9. He decides to Take the Best for a result of 19, and the GM describes that Phineas takes almost 40 minutes finding and constructing the perfect hiding place, from which he observes the conversation without detection.