Time for a new back tyre? Age/mileage

[Hugo Stiglitz]

2021 bike on 12.5k. Tyre is no doubt original - Feb 2020. Time for a change? Tread looks good.

[trickywoo]

1mm or 7 years for me.

Profile is also important. I’d change a squared off tyre because one with a good profile is much nicer.

[KTMsm]

I'm not sure I understand the question

IIRC you can sell a 5 (might be 4) year old tyre as new

If it isn't square and has tread what's the problem?