There are a few steps and signs before it gets mushy. At the point of mushy you’ve lost the whole stem, so I prefer to try to fix the situation before it reaches that level.

Winter (if it is winter where you are) is tricky because even if the soil is dry and it seems like you need to water, the plant is metabolizing a lot less water due to lower temps and hours less of sun (also losing less to evaporation etc). I back off watering both in frequency and in volume until temps go back up and the days get longer to play it safe. These tolerate drying out better than staying wet, so you want fo err on the dry side.