If the watering is on the too-little side for the evaporation and plant size going on, well, the plant will look a little sad for a bit. Then you water it, and it goes back up and looks happy again. This is a situation plants regularly deal with in the wild - drought - and they have adapted to it.
If you water too much, especially with bad drainage, there will be stagnant water in the pot, roots rot and the plant dies with little recourse.
So now I make sure my pots can drain, take my plants outside once or twice a week, absolutely drown their soil and let that drain for an hour or two. This way, the soil becomes saturated without stagnant water and... some of these plants are reproducing and growing at unreasonable rates for the amount of effort placed into them.
Avocado on the other hand grows like a charm.
Labor of love (beautiful trees), but they are very iffy trees to get going. I did attempt to help things along by putting lots of madrone duff with it, so as to try to get the right biota.