Think about it.  You can add water to a dry plant but try removing it from a drowning plant.  When you give out watering instructions let your clients know that some brown edges on the leaves is an indication that you need to water.  It doesn’t mean the plant is dead.  Also, while watering in the morning is best it doesn’t mean that you cannot water in the evening.  Honesty is the best policy.  Encourage your clients to be honest about their watering practices when they contact you with concerns about a plant and ask for photos.  We have the technology so let’s use it.  After all, a picture is worth a thousand words.