Q.bat plants
I have had two bat plants for a couple of years now. They have very healthy leaves but, alas, no flowers. How often do they flower, please, and how long do the flowers last? I saw the parent plant in my neighbor’s garden in flower when I received mine, but hers hasn’t flowered either for two years now.
Thank you, Shirley.

Certified GKH Gardening Expert
The bat plant, botanical name Tacca chantrieri, begins blooming when it's 2 or 3 years old. If you grew yours from seed, it simply might not be old enough yet, but you should see flowers next summer.
Here are some general reasons a plant may not flower:
https://www.gardeningknowhow.com/plant-problems/environmental/plant-not-blooming.htm
Although the bat plant shouldn't be in direct sun and should be planted in shade outdoors, they do need bright indirect light to flower indoors.
Nutrients are a common culprit: excessive nitrogen levels or lack of phosphorus will inhibit flowering in most plants.
See this article for more on bat plant care:
http://gardeningsolutions.ifas.ufl.edu/giam/plants_and_grasses/flowering_plants/bat_flower.html