First and foremost, sealing quarry tile is unnecessary.
There are ultimately only two factors that may persuade you to seal: convenience and aesthetic.
In terms of convenience, consider how frequently your tile will encounter messes. Sealing quarry tile will make cleaning easier, thus offering an advantage in environments where messes are occurring on a daily basis. If you are anticipating frequent accidents then you would likely prefer a floor that is easier to clean. When it comes to aesthetics, ask yourself if you are desiring a specific look. Sealing quarry tile will give it a sleek, glazed appearance. If that is your preference, then sealing will allow you to have that polished look, while still maintaining all the benefits of the quarry tile.
It is important to note that after the tile has been sealed it will require maintenance. So if constant cleaning is of no concern to you, and if you prefer the look of unglazed tile, then opting out of sealing tile will make life easier. If you choose not to seal your tile and find yourself changing your mind later, don’t worry, tile can be sealed at any point!
Examples of sealed and unsealed tile at the Hotel Mission De Oro in Santa Nella, CA:
Sealed tile in the banquet hall.
Unsealed tile in a walkway / outdoor space.