There are many doubts regarding when to water a plant and when not to and discussion results in almost watering the plant every time. Among All the plant health cases we get almost in 80% of the cases the issue is caused by OVER WATERING!
Water being easily available resource we keep on showering our care on plant through over watering.
We must be aware that each plant species tolerates drying out to different levels. For example succulents and cacti prefer complete dry out before watering. On the contrary, fern and calathea won't be happy when they dry out. Where as Hibiscus, Rose plants prefer to be watered when the top 2 3 inch is dry.
You don't have to stick your finger into the soil to check the moisture content in it. If you don't want to dirty your hands, you can grab a TOOTHPICK instead!
Insert it 2-3 inches into the soil. You can judge whether the soil is WET, MOIST, DRY by just taking the toothpick out and observing how much soil sticks and clings to the toothpick surface and how soaked it is. Water the pot only if the the toothpick is completely dry, else wait for one or two days.
Just remember enough watering is the key to keep your plants healthy.