How Do I Choose Between a Hash Table and a Trie (Prefix Tree)?

Question

So if I have to choose between a hash table or a prefix tree what are the discriminating factors that would lead me to choose one over the other. From my own naive point of

Answer 1

Some (usually embedded, real-time) applications require that the processing time be independent of the data. In that case, a hash table can guarantee a known execution time, while a trie varies based on the data.