I've read a text by Scott Adams on his Book The Joy of Work. This is about bringing humor to the workplace. He cites that if there are 2 of at the 6 types of humor then it would really be funny. I think that the same rule could be applied to magic.
In Magic there are eight basic effects namely:
I think that a trick with one of these effects is good but having at least two effects in one trick makes it a powerful one. The simplest example is when doing a vanish and producing the vanished item in an unexpected place. Another example, when I do a coin transposition in a participant's hand trick, I could use a transformation first before revealing the coin has transposed from one hand to another.
However there are tricks that are exception to the rule. These tricks are usually of the prediction nature. Prediction alone is a very powerful effect. Adding the other effects only arouses suspicion when obviously applied and thus changes the whole nature of a trick.
In my opinion by combining two effects for a trick makes it a standalone piece that could be used for routines. However don't forget to add less powerful tricks, since magic is not all about powerful tricks it's about combining the right tricks to achieve a good routine. Adding the "in-betweens" makes a routine more interesting and more memorable to participants.