When the pot stays wet
Persistently wet mix can limit oxygen around roots.

What to look for
Check below the surface, the pot's weight and the drainage holes. Yellowing or wilting can happen with excess water, but they can also have other causes. Different plants need different drying intervals.
What to do
Empty standing water, make sure the pot drains and wait until the mix reaches the appropriate dryness for the plant. If it stays wet or the plant keeps wilting, check for compacted mix and soft roots.