Spoken like a guy who doesn't know how to solve big problems if you ask me. In any optimization problem I've ever been associated with, this is exactly the opposite of the correct strategy. You go after the BIG stuff first not the little stuff because:

a) It's big, not small.

b) You find that once you have gotten the big stuff, your perspective shifts and there is even MORE big stuff you hadn't noticed before.

c) "Momentum", while a fine physical analogy for getting a train moving, doesn't apply generally to accounting and budgeting.