Would you rather save a bishop, or knight?

I think bishops, It simply dominates discover attacks and can capture from a long distance. While knights are great for forks and that, you don't get much options with the knight. The knight is an early game piece, I believe. It can go 2 squares either side, flick. And the distance is restricted.

It depends what part of the game it is for me.

Closed pasition ill take knights, open positions favour bishops... Somtimes id rather have a pawn then a rook. It all depends on the position

This question came up in the past. The IM answer is that a Bishop us more valuable in all phases of the game. That said, at my own discretion I might chose a Knight depending upon the position or because it's better at proving for mistakes under the pressure.