No — for most front- or rear-wheel-drive vehicles, replacing one or two tires is fine as long as the others still have solid tread. All-wheel-drive vehicles are the exception: uneven tread depth strains the drivetrain, so manufacturers generally want all four matched closely. Sacramento Tire Shop checks your drivetrain before recommending a partial or full set.
Why does it matter whether the car is all-wheel-drive?
On a front- or rear-wheel-drive vehicle, each axle mostly does its own thing, so a new tire on one side next to a half-worn tire on the other isn't putting unusual stress on anything — it just means slightly different grip side to side, which most drivers won't notice on dry pavement. An all-wheel-drive system is different: it's constantly comparing how fast each wheel is turning, and a tire with less tread has a smaller rolling diameter than a new one. That mismatch makes the system think one wheel is slipping when it isn't, and it can wear out the drivetrain components that are supposed to correct for it.
This is also where the case for four gets stronger the longer you wait. A car that needed one tire eight months ago and needs a second one now often ends up needing all four eventually anyway, just spread across two separate bills instead of one — worth asking about upfront rather than discovering it later.
What if I only need one and the tread on the others is close?
If the remaining three still have most of their tread and the vehicle isn't all-wheel-drive, one tire is often genuinely enough — Sacramento Tire Shop, rated 5.0 from its Google reviews, would rather tell you that than sell you three you don't need yet.
How close does tread depth have to be on an AWD vehicle?
Close enough that manufacturers generally recommend replacing all four together rather than mixing depths, since the drivetrain reads tread depth as wheel speed. If you're not sure whether your vehicle is affected, it's worth asking before buying just one.
What if I can't find the exact same tire I already have?
That happens, especially with an older or discontinued tread pattern — the shop will look for the closest match in size, load rating, and tread depth rather than assume any tire in the right size will do. On an all-wheel-drive vehicle, getting that match close matters more than it would otherwise.