Information has a price

Strong players often spend a small piece early, on purpose, just to learn what a hidden piece is. They fall behind in material and gain knowledge that shapes every later move.

A rough way to weigh it: how likely is the probe to tell you something useful, times how much that knowledge is worth, compared with what you give up. If the chance is one in two, the knowledge worth eight, and the cost two, the probe is worth about two in your favour.

The same reasoning applies off the board: a test, a second opinion, a small experiment. Paying for information is sensible when what you would learn changes what you do next.