Somebody set your new/used/CPO split once. Maybe it was the agency rep during onboarding. Maybe it was a GM who eyeballed last year's stock mix and picked a round number. Whatever the origin, that split is very likely still running today — untouched — while the incentive strength, the stock mix, and the feed age underneath it have all moved multiple times since.
This isn't a minor configuration gap. It's the budget decision with the most P&L leverage in the account, and it's the one most dealers never revisit after week one.
How Much Do Dealers Actually Spend on New vs. Used Advertising?
NADA's 2025 dealership financial profile puts average franchised-store advertising spend at roughly $739 per new vehicle sold — up modestly from the prior year — even as total industry ad spend approached span0 billion. The bigger story isn't the topline number; it's where that spend is going, and whether the new/used/CPO mix behind it is a deliberate allocation or a default nobody revisited this year.
That same reporting put the ad-to-sales ratio at 0.77% of total dealership revenue for 2025. Those are big, serious numbers for a line item that, inside most stores, still gets set once and revisited never.Zoom into the new-vs-used split specifically and the picture gets murkier, not clearer. A franchise-dealer advertising study from the Radio Advertising Bureau found that used-vehicle-specific advertising typically accounts for only 20% to 30% of a franchise dealer's combined new-and-used advertising budget. That's a wide range on its own — and it's a static range being applied to an inventory mix that is anything but static. Used and CPO units move through the incentive calendar, the OEM allocation calendar, and the aging curve on completely different timelines than new units do. A split calibrated for March rarely still fits in July.
Why Doesn't Anyone Revisit the New/Used/CPO Split After Onboarding?
The honest answer is that revisiting it requires a judgment call, not a lookup. Getting the split right in any given week means weighing at least three things against each other simultaneously: current OEM incentive strength on the new side, how many aging used and CPO units are sitting past their optimal turn window, and the actual per-unit advertising economics each condition bucket is producing right now. That's a reasoning task. Most dealer accounts don't have anyone doing that reasoning on a recurring cadence — they have a percentage typed into a platform a year ago.
Agencies don't fix this by design. A channel rep gets paid to manage the channel they were staffed on, not to reason across new-vs-used-vs-CPO economics for a client they see once a month. The same structural gap that keeps agencies from unifying budget across channels keeps them from unifying it across inventory condition, too — it's a second axis of the same problem, and it gets even less attention than the channel-level one because it's buried one layer deeper in the account.
What Changes Week to Week That the Original Split Doesn't Account For?
Three things move constantly, and none of them move on the same schedule:
Incentive strength. OEM lease cash, APR subvention, and loyalty offers shift monthly, sometimes mid-month. A new-vehicle incentive that justified a heavier new-side allocation in Q2 can lapse entirely by Q3 while nobody adjusts the split that was built around it.
Feed age. Used and CPO units carry an aging clock new units don't. A used unit sitting 45 days past its optimal turn window needs a different advertising posture than one that just hit the lot — and a fixed percentage split has no mechanism to notice the difference.
Stock mix. Dealers sold more than 13 million used vehicles last year, up roughly 2% year over year, at an average selling price near $28,680. A store whose used volume is growing faster than its new volume is, by definition, running a stale split if the percentage hasn't moved with it.
None of these shift on a monthly cadence. They shift on whatever cadence the OEM offer calendar, the used lot's aging report, and the sales floor's actual mix happen to move — which is closer to daily than monthly. A split set once a year is being asked to track three variables that don't even move in sync with each other.
Is There a Right New/Used/CPO Ratio Every Dealer Should Use?
No — and any vendor telling you there is one hasn't looked at your incentive calendar or your used-lot aging report. Used vehicles typically carry higher front-end gross profit per unit than new vehicles, which on its own would argue for weighting used more heavily in most media plans. But that argument only holds when the used inventory is fresh, priced right, and not sitting on aging incentives of its own — and it can flip entirely in a month where a manufacturer drops an unusually strong new-vehicle lease offer into the market. A fixed ratio treats a moving target as fixed. It's not a strategy; it's a placeholder that was never removed.
What Does a Correct Budget Split Actually Require?
It requires the split to be re-evaluated against current conditions on a cadence that matches how often those conditions actually change — not a cadence set by whoever last opened the ads dashboard. That means reading the current OEM incentive calendar against the store's actual stock mix and actual feed age, every time the inventory picture changes, and adjusting the new/used/CPO allocation accordingly. It also means the dealer needs a way to say "not this bucket" when there's a business reason — a franchise requirement, a floor-plan constraint, a strategic bet on used — that the data alone wouldn't surface. A system that reasons well but can't be told to stop is just a smarter version of the same problem: someone else's judgment overriding yours with no way to hold your ground.
The AUTONOMi Approach to the New/Used/CPO Split
On every inventory refresh, AEGIS re-judges the dealer's spend split across new, used, and CPO against the store's live stock mix — weighing per-unit advertising economics, current OEM incentive strength, feed-age pressure, and seasonality as a reasoned judgment rather than applying a fixed stock-share formula.✓ Jul 18 This isn't a monthly re-forecast. It runs on the same cadence the inventory itself changes, because the inventory picture AEGIS is reacting to is refreshed directly from the dealer's own site, not from a stale monthly export.
Until a dealer sets their own new/used/CPO split, AEGIS's daily re-judgment applies automatically inside the approved budget; the moment a dealer sets a split themselves, AEGIS honors it, and any further adjustment ships as a recommendation the dealer approves with one click rather than a change that fires on its own.✓ Jul 18 The judgment doesn't disappear when the dealer takes the wheel — it moves from autopilot to advisor.
Any sub-channel or inventory-condition bucket can be locked in Budget Studio: a locked allocation is one AEGIS optimizes freely around but never moves beyond a narrow governance band, and setting that lock flips the affected surface into ask-permission mode for anything beyond it.✓ Jul 18 Everything left unlocked stays fully fluid, continuously re-solved against current conditions. That's the actual shape of the trade-off this article has been describing: a dealer holds exactly the ground they mean to hold — a CPO floor for a strategic push, a new-side ceiling tied to floor-plan cost — and delegates the rest to a system that's re-running the judgment call every day instead of once a year. Every lock, unlock, and allocation shift is hash-chained into the dealer's own decision audit trail, so the reasoning behind each move is traceable after the fact, not just asserted in the moment.✓ Jul 18
Where This Goes From Here
The dealers who will lose share over the next two years aren't the ones with the wrong split. They're the ones whose split was correct in March and has quietly stayed frozen since, while three-plus generations of OEM incentives and two full aging cycles moved underneath it. A budget split is not a setting you configure once. It's a judgment call with a shelf life measured in days, and treating it as a config field is how dealers end up over-advertising units that don't need it and under-advertising the ones that do. If you want to see what your own store's split looks like against your actual incentive calendar and stock mix right now, model your dealership's current spend allocation before you set next month's number the same way you set this month's.
