When he presents his technology budget to senior management, Edward Granger-Happ likes to talk about a ’57 Chevy.

“I tell them that we have to polish it and take care of it, and [because] it’s a ’57 Chevy, we’re living on borrowed time, especially if we’re using it for the daily commute,” says Granger-Happ, CTO at Save the Children.

The spiffy car is a metaphor for a legacy system in use at the foundation, and it helps Granger-Happ make several points. First, it puts the old system in a context everyone on the business side understands. Second, it helps him make the argument that systems not only come with maintenance costs but that those costs grow (and take up more of his budget) as the systems age. Third, he can tie maintaining or replacing the “Chevy” to his strategic IT plan, priming the group for a future discussion.

Granger-Happ says his approach to talking about the IT budget usually gets him what he wants at the $400 million nonprofit. His budget for the coming year is $4.7 million. But he also knows that when the foundation sees fund-raising tighten, as is the case for the coming fiscal year, he knows he won’t get major new initiatives funded, and he doesn’t ask.

Though it may take up less than an hour at the executive committee or board meeting, the budget presentation is one of the most important messages a CIO has to deliver. What a CIO says and doesn’t say—during both the actual presentation and in the months leading up to it—sets the course for IT not just for the next year but, where new investments are concerned, for years to come.

Yet despite its importance, few elements of such a presentation are universal. What matters in a budget presentation depends on the priorities of the company and the personalities of the CEO, the CFO and the board. That said, all successful budget presentations do need to make a clear business case for spending and especially for new initiatives, and CIOs had better have support lined up from the business units that should benefit. The presentation itself needs to be concise and free of technical jargon.

Granger-Happ also says to tread carefully without being too clever, recalling the once popular comparison between the relative cost of computers and cars. “You remember that comment that if cars were computers, Rolls-Royces would cost $1,000 and get 100 miles to the gallon?” he says. “It was pretty easy for [someone] to come back and say, But they’d lock your windows every other week and crash without warning.”