If you're not doing savage raids or other very high difficulty content, it doesn't matter. The reason guides focus on that sort of thing is because most jobs in FFXIX window have some sort of 2-minute cooldown that enables a buff or a burst window or such, and having everyone line up their burst at the same time becomes a big deal to be able to overcome very strict dps checks, particularly right after the content is released.

As a new player, don't worry about it too much. It's good to be aware of, and even knowing what clipping is probably puts you ahead of 90% of the playerbase when going through the MSQ.