Tire replacement

Somehow I've gotten out of synch in the timing of the replacement of my two main gear tires. Is that ok or should both mains be replaced at the same time when one tire becomes damaged and there is moderate or worse wear? I think that is proper procedure for automobile tires and seems like it would apply to airplanes as well.

Thanks
Erich

I don't see any reason why....... just replace the tire that needs to be replaced with like tire.