Pruning a fruit tree

[Corzhens]

Sugar apple is a small tree with branches that grow up to 10 feet at the most. What we had learned from the orchard people is to regularly trim the sugar apple so it would bear fruits regularly. That's what we have been doing ever since. Our first sugar apple was planted in 2003 while the second is already a scion of that, we planted 3 years ago. Both trees are in the front yard since they love sunshine.

What other trees do you know that needs pruning?