Used tyres can be a good way to save money, but only if you know what to inspect. Many people look only at tread depth and assume the tyre is fine. In reality, a tyre may be old, hardened, repaired or unevenly worn even when the tread still looks acceptable.
The first thing to check is the DOT marking, which shows the production week and year. A very old tyre may not be a good buy even if it seems lightly used. Rubber ages with time, becomes harder and may lose grip before the tread is gone.
Look closely at the inner and outer shoulders of the tyre. If one edge is much more worn than the other, it can point to poor alignment, incorrect pressure or suspension issues on the previous car. That is not just cosmetic, it affects road behavior.
Inspect for cracks, bulges and repairs. Damage on the sidewall is especially important because that area of the tyre works under significant stress. If something feels questionable, it usually is not worth gambling for a small price advantage.
If you are buying several tyres together, make sure their age and wear level are reasonably similar. Mixing tyres in very different condition can affect handling more than many people expect.
It is also useful to ask what car the tyres came from and why they are being sold. That will not always reveal everything, but an honest seller usually answers calmly and clearly. Vague explanations and pressure to hurry are often bad signs.
If you are not confident judging used tyres yourself, bring someone more experienced or have them inspected before fitting. A good used tyre can be a smart purchase, but a bad used tyre is savings in the wrong place.