In some circumstances, you may need to obtain a quiver early, for exemple if you performed Early Master Sword and clipped inside Mother & Child to get Fire and Ice Arrows instead of the bow in TotG. Since the Fire and Ice arrows, as well as the Light Arrows, give you a bow but not a quiver, they won't be usable before obtaining one. That is where entering Fairy Fountains early can become useful.
If you have chest storage, you can clip inside fairy islands by walking very slowly in the back of the island.
Note: Getting a quiver or bomb bag early does not give you the bow or bombs as usable items.
Same as with chest storage, if you have door cancel you can phase through the walls of the fairy fountains to enter the loading zone.
If you enter Thorned Fairy Island early specifically for an early quiver, the only thing preventing you from exiting normally (without savewarping/deathwarping) are vine tentacles. It is possible to get around them in 2 ways: