If it seems like I am writing about evidence again, it is because evidence is such a frequent issue on appeal. In criminal law, many evidentiary issues are first brought to the court’s attention in a motion to suppress, when defendants try to have evidence gathered against them thrown out. And what happens in that hearing is critical for the appellate attorney because appellate courts decide their cases based on the record developed below.
So a defendant who never moves to suppress a given piece of evidence cannot be heard later to say the court should have suppressed it anyway. And if he did not give a certain reason for it, (for example, the search being unconstitutional), he won’t be able to develop that argument on appeal (for example here, why the court should have declared the search unconstitutional).
It is a good idea then to involve appellate attorneys from the start in such matters, to protect your rights later.