Is it a bad idea to buy just one new tire?

I blew a tire yesterday, and the AAA man said it can’t be repaired. I am not automobile-savvy at all, but the hole sure looks convincing.

My car is 4 years old (bought new), and I don’t expect to outlive it. It has less than 10,000 miles on it; I bought it following retirement, and I don’t commute any more—mostly just do errands around town.

My husband says the tires that came with the care are probably rated for 20,000 miles and I might as well go ahead and upgrade all four now rather than just replacing one.

What would your advice be, based on your knowledge and experience?

And—any brand recommendations? I’m in Northern California; no snow or ice.

Tags as I wrote them : cars, automobiles, tires.