My avocado tree grown from seed finally produced fruit for a few years. Grafting didn't work, but I had bought a little seedling, put next to it, which helped it grow fruit. That little seedling has died. My avocado treat hasn't produced fruit in awhile. Does it need a new seedling? I thought once it grew fruit, it would continue to do so.
If your tree is producing flowers but no fruit, this might be a pollination issue. See this article for advice:
If there are no flowers at all, it might be that your tree doesn't have enough nutrients or other resources. Here is more information: