Boy, watering depends on so many variables. No one right answer. I can tell when my finger is wet. I'll bet you can to if you put your mind to it. Water it, watch to see how fast the water sinks in (a measure of how porous your soil mix is.) Should not drain out immediately, should not pool for a while. Use that finger and do not water it again until the soil is dry 2" down. Once every 2-3 months, water it from the bottom - sit the pot in a tub of water until the top gets moist. Biggest problems with that plant might be too little light ( they leaves get further and further apart,) or Spider Mites. Otherwise a nice plant. Will take a lot of abuse. Just for fun, Google Dracaena Draco in the Canary Islands - pix. Maybe your will get that big in another 800+ years. Gene