I honestly didn’t pay attention to it at all, and realized in my early to mid-30s that I hadn’t done it. So I just told myself I wouldn’t bother until 40.
But I also, afterword, paid attention to, notably, when and how I died.
And I basically ascertained that there were maybe 2 times that I died that if I had talented out, I may not have (i.e. I would have killed the mobs fast enough to survive either through more DPS to shorten the fight, or more health/dodge/whatever to endure it). The fights were that close.
Otherwise, both solo and in groups, we either clobbered the mobs, or they clobbered us – decisively. Talents wouldn’t have saved me either way.
Kind of jaded me on the whole thing, honestly. Yea, it matters, but, not really.
At one point, being I was a disenchanter (I had enchanting-1 so I could DE drops), I obviously managed to swap out a green leather piece for my blue plate piece, and subsequently DE’d it thinking it was just an extra drop.
I have no idea how long I ran around as a L60 warrior with a L40ish green leather chest piece instead of an L55+ish blue plate piece. Someone noticed while waiting for the boat in Menethil. Whenever it happened, I didn’t notice it missing.
Mobs dies, I didn’t. Since I didn’t run around running meters, my basis of performance was pretty simple. “Did I die? No? Doing good then!”
In the end, I honestly don’t recall when I talented up at 40 if I noticed much of a difference. The biggest difference I noticed at the time was the Whirlwind Axe – it’s such an OP weapon at that stage of leveling. It’s just – POW! WHAM! You can feel that sucker.
Talents? I’m sure I measurably performed better, can’t say I noticeably performed better.
