One Bite? two bites of an apple

What it means is when a party tries to get a second chance at something where in fairness they should (arguably) have only one shot.

For example, I had a case a few months back where the other side decided not to call a key witness and lost the case. It then appealed, asking for another hearing to present the testimony of that witness. In effect, they were asking for a second bite at the apple. 

What's unfair about it is that 
(1) the other side gets the benefit of preparing its case with full knowledge of my case; 
(2) it's kinda analogous to double-jeopardy; and
 (3) the other side is saving time and resources at the expense of my client by first presenting a limited case and potentially making my client appear twice.