Yep.
Is it usually best to capture in decreasing order of piece value?
Sort:
“Or is every situation totally unique and you need to calculate all the possible captures in different orders in every case?”
Yep.
Yep.
Yes and Yes.
"is every situation totally unique and you need to calculate all the possible captures in different orders in every case?" ++ Yes, you have to calculate.
"is it usually best to start capturing with the piece of lowest value and finish the sequence with the piece of higher value?" ++ Yes, that is often true, but not always.
In a position where a complex series of captures can happen is it usually best to start capturing with the piece of lowest value and finish the sequence with the piece of higher value? Or is every situation totally unique and you need to calculate all the possible captures in different orders in every case?