During the dry season, you should be watering your mango. Twice a week for 10 minutes seems to be a good pattern. Consistent watering prevents fruit splitting and helps with nutrient uptake. Since our soil tends to be shallow sand, it dries out very quickly.
Gummosis is often a symptom of copper deficiency, which can be an issue in our high pH soil.
While some mango trees can be "set it and forget it," you really want to establish a consistent fertilization regimen, especially if you have shallow Broward soil underlayed with builder's fill. My favorite mango combo right now is Har's slow release 0-3-16 with minors and sulfur to lower pH.
Lastly, a fungicide program is extremely beneficial. A good copper fungicide product once a month helps stave off anthracnose and provides copper, which is often lacking in our soil.