Star Trek: 10 Starfleet Rules You Never Knew Existed

This has been talked to death about, but it's worth mentioning that Starfleet had a warp speed limit in place that was almost always disregarded.

In the Next Generation episode Force Of Nature, the crew discovered that warp travel was slowly damaging the fabric of subspace, which could render warp travel and subspace communication impossible throughout huge regions of the galaxy. To slow the process until an alternative form of propulsion could be developed, Starfleet instituted a maximum speed limit of warp 5 throughout Federation space except in extreme emergencies.

These rules wouldn't have applied to Voyager (as they were stranded on the other side of the galaxy), but all throughout the rest of The Next Generation, as well as Deep Space Nine, Picard, and Lower Decks, we've seen starships ignore this limit and go far beyond warp 5. At this point, most fans assume that countermeasures were developed shortly after the episode, removing the need for the speed limit. In fact, according to Memory Alpha, the 3rd edition of the Star Trek Encyclopedia and an unpublished Voyager technical manual explain that Voyager's folding nacelles were designed specifically to reduce damage to subspace, explaining why they raised whenever the ship went to warp.