When playing two-handed pinochle, the 'normal' rules of the game are suspended during the initial phase (when melding takes place along with trick taking while depleting the deck of undealt cards).
In other words, you cannot yet renege, you are not penalized for not following suit, you are not forced to out-trump trump, etc.
In this phase of the game, what is the best way to determine if it is a good idea to use trump cards?