Do you continue adding soil to the pot over time?

After each watering, the soil becomes a little more compacted, and the soil line drops a little bit. So, do you keep adding more and more soil throughout? Is there any benefit to doing so?

When you initially fill adn water your pot, it will contract a bit, and so it is perfectly normal for you to add more soil on top. This compacting of the soil should not happen throughout the grow though. Only during the intial waterings of the soil when freshly potted up.

And yeh, you can just add more soil if you like...or leave it be...which is what I do...