Q.Dieffenbachia Lily
I have had a Dieffenbachia Lily for about 18 months with no problems. Lately, the leaves have started to yellow. It does not require watering and it has been put in good light. Please advise.

Certified GKH Gardening Expert
While they do not require much water, they do need some water to survive. Water the plant when the soil is dry.
If you have been providing water, it may be a fertilizer issue (though they need little fertilizer) or it may be rootbound. Check the roots and give it some 1/4 strength water based fertilizer.