You should place a GTT Order in the following cases:

  1. You want to enter a trade at a specific price in the future.

  2. You want to exit the trade at a specific price: In this case you can add a Stop-Loss to limit losses and Profit Target 

With GTT you don’t need to track or place orders everyday for a Stock/script that you’re interested in and the 
order stays in the system for multiple days.