Building a car fund, envelope by envelope
A single "car savings" pot is easy to open and easy to raid. Five labeled envelopes are harder to argue with, because each one knows what it's for and roughly when it will be spent.
A sinking fund is money set aside a little at a time for a bill you know is coming, whose date or size you can only roughly guess. A car generates at least five of them. Keep them in one account if you like — a note or a spreadsheet can track the split — but think of them as separate envelopes, because they fill at different speeds and empty for different reasons.
The fill levels below belong to an illustrative household partway through its first year of doing this. The dollar targets are theirs too, chosen for the example. Yours come from your own car, your own policy and your own paperwork, and each envelope says where to look.
Sized by the set, spread over its life
Start with a quote for a full set of the size your car takes, mounted and balanced. Then estimate how long a set lasts you: the tread-life rating on the sidewall paperwork gives a rough ceiling in miles, and your own annual mileage turns it into months. This household's set was quoted at $800, and a 40,000-mile set at 12,000 miles a year lasts about 40 months.
Resist topping this envelope up early. Tires wear on their own schedule, and the tread depth tells you more about timing than the calendar does.
Sized by last year's notice
The easiest envelope, because the bill is printed for you. Find last year's renewal notice and add anything that rides along with it where you live — an inspection, an emissions test, a local vehicle fee. The fees and schedule vary by state, and some renew every two years; the office that handles vehicle registration in your state lists what applies. This household's total was $180, once a year.
If the amount changed last year, use the new figure. Registration charges in some places are tied to the car's value or weight, so they can drift.
Sized to one claim, then left alone
This envelope has a ceiling, not a rate. Fill it to your collision deductible — printed on your policy's declarations page — and then stop. If you carry different deductibles for collision and comprehensive, fill to the larger. This household chose a $1,000 deductible and set out to fill the envelope over ten months.
The envelope and the deductible are one decision. A higher deductible lowers the premium only if the cash to cover it actually exists; choosing a deductible works through the break-even.
Sized to the repair you'd hate to put on a card
No one can tell you what your car will break next, and we won't pretend to. What you can decide is the size of surprise you want to absorb without borrowing. Look at the car's age and mileage, the maintenance schedule in the owner's manual for anything large coming due, and any repair quote you've been putting off. This household picked $1,500 as its line.
Refill it after every use before any other envelope gets extra. A deeper method for sizing this one is in how big a car repair fund should be.
Sized backward from the day you'll need it
The slowest envelope, and the one that changes what your next car costs. Pick a realistic month when this car will be replaced, pick a down payment you'd like to bring to that day, and divide. This household expects to replace its car in about four years and wants $6,000 in hand.
If your car is paid off, a natural amount is the old loan payment, still leaving your account each month, just to yourself.
What the five cost to feed
| Envelope | While filling | Once full |
|---|---|---|
| Tires | $20 | $20 |
| Registration | $15 | $15 |
| Deductible | $100 | $0 |
| Repairs | $100 | $0 |
| Next car | $125 | $125 |
| Per month | $360 | $160 |
The two columns are the useful part. For its first stretch, this household feeds the envelopes $360 a month. With $700 still to go in the deductible envelope, that one fills in seven more months; the repair envelope, $1,200 short, fills in twelve. After that the monthly draw falls to $160, and stays there until something is spent. The early months are the expensive ones, which is exactly when most people give up on the system. Knowing the number drops is often what keeps people going.
Rules that keep the envelopes honest
An envelope is spent only on its own label. The tire money doesn't pay for a brake job, even though both keep the car stopping. If one envelope is empty and another is full, move money across deliberately and write down that you did, so you know which one to rebuild.
Refill order matters. After a withdrawal, refill the deductible and repair envelopes first. They protect you from the bills you can't schedule. Registration and tires can wait a month; a collision cannot.
Resize once a year. Put a reminder on the date your registration renews. Check each target against the new notice, the latest tire quote and your current policy. Targets drift, and an envelope sized three years ago may be quietly too small.
Keep them boring. This money needs to be there on a bad Tuesday. A savings account you can reach in a day is the right home; anything with a market price is not. Some banks let you name several savings buckets inside one account — check whether yours does — but a single account and a five-line note does the same job.
If you're not sure which bills belong in which envelope, the car bills that arrive once a year sets them out month by month. Start with whichever envelope scares you most, and the rest will follow.
Keep reading
Further reading
- What a sinking fund is Investopedia
- How an emergency fund works Investopedia
- Car ratings and reliability Consumer Reports