Mine visibly droops when thirsty, and I water when it does, not before so as not to cause root rot. It was thirsty this morning and I watered, so not so obvious now, but they look like this:
Upper leaves have already started to perk up...you can see the leaves hanging down more on the lower branches in the photo to the right.
My tree is nearly pot bound with only about 1-2 inches of space between the root ball and the side of the pot. Look at the trunk diameter vs. the size of the pot. How big is your plant and what size pot is it in? Notice I cut leaves that yellow and fall into strips or crumble up crisp dried ones to use as mulch to help keep the soil mix from drying out, and to feed the worms living in the soil.
If you are not sure how much water it needs, it's a good idea to saturate and let water drain out of the bottom of the pot and fill the catch tray. Leave the pot sitting in this to soak it back up as needed for no more than 2-3 hours, then completely empty the catch tray, making sure to eliminate additional water that may come out of the pot. I do this once a month or so, but just water in between.
Where you live and current season / weather / climate / growin conditions will make a difference, too. Right now, mine is in the house in the family room, but it will go outside once the weather warms up, and then it will need to be watered once a day or every other day.