Time to replace the spare?

Just had to use my spare tire for another 12 or so miles. I've used it a few times before, but of course it's also coming up to being 10 years old (bought the car in June 2012). Best to replace?

I see that TireRack is speccing choice of the Maxxis Temporary/Compact Spare (T135/80D16 101M) for $138.17 and the Yokohama Y870B (T135/80D16 101M) for $94.59. I figure the Yokohama should be good enough.

Thoughts?

Sidenote: I was going out yesterday morning and drove a block before noting the tire pressure light was on. Went home and found the right/rear tire was at 20psi; front right was at 27. I filled both tires and went to a local Mavis. They checked the tire over but found nothing. The tires were... a little over four years old, I think. Normally I would just fill them up and see what happens over the next week, but on Monday I have to drive my 91 year old mother to NYC for some medical tests (1-/2 to 2 hours with traffic) and didn't want to risk getting ready to go and having a flat, so I opted to replace all four.

While doing this, they said the struts needed replacement. They showed them to me, but I'm hardly expert enough to know the truth of it. But I had them replaced, too. So... $2k later I drive out, feeling perhaps a bit suckered.

As I'm leaving the lot I hear a TAP TAP TAP sound, which to me means a pebble stuck in a tread, or maybe a nail. I get home but can't see anything. The next day I'm on the parkway and the front/right tire explosively depressurizes. Back to Mavis (on the spare). My presumption here is that the tapping sound was a nail in the tire, something they drove over while test driving the car after the strut work. I saw a small hole in the tread after removing the tire, though perhaps the nail or whatever came out when the tire died.

If I hadn't driven today this would have happened on the Long Island Expressway on the way to NYU Medical Center.