New Delhi, Sept. 24 -- Buying a luxury car often starts with a simple question of which model fits the budget. But there is another decision that can have a much bigger impact on the buyer's finances, whether to buy the car new or choose a pre-owned model.

A new luxury car offers a full warranty, a clean ownership history and greater certainty about its condition, but the buyer also absorbs the steepest depreciation in the early years. A pre-owned car can offer a much more expensive model at a lower price, but the saving can be offset by higher financing costs, maintenance, repairs and limited warranty cover. The real comparison, therefore, is not just the price of the car today but what it will cost to own and eventually sell.

"The pur...