How Old Are Those Tires?

My tires are 14" Titan ST Radial II. After a blow out last Sept. on the tires that came with our used TM, 3 months after we got it, we had both tires replaced. It was difficult to find a supplier of trailer tires so we we're happy to have anything that fit even though they cost more than my car tires. While following the thread on "another blowout", I thought to myself, "at least I don't have Marathons." Then found that Titan has connections with Goodyear and Firestone, so how do I know what I really have? How does anyone know? The folks who sold me the Titans (at Big O) told us about the dating on the tires. That was good info. When we bought our first TT, a Coleman, in 2002 it was brand new. It had 13" Dutro tires. Each one of them disintigrated over the first 2 years. Even the spare. No blow out, just all the tread fell off in fist sized chunks. We were told it was just the way trailer tires are. We mostly blamed Interstate-5 and stopped driving the 400mi trip to LA with the trailer. If we had known about the date of mfg on the tires back then, we probably would have found them to be quite old even though they were "new" in that they had never been used.
So now I vow to check the tires I buy more carefully for mfg dating and replace them every 3 years regardless of usage, and keep tire pressure in check. But I wonder how much this will help.

So here's my question. If you have had a blow out due to a tire malfunction, how old were your tires when they blew? I know many won't know the mfg date but how long were they on your trailer? Were you pushing or exceeding the 5 year reccomended limit? Were they under 3 years old? I'd just like to get an idea. I know there are lots of variables but I don't remember reading anything about "brand new" tires failing (except my own). Does it happen?
Thanks in advance.
Paranoid,
Cheri