No.1554
I don't hear anyone talking about this, but it seems pretty apparent to me. Particularly from playing heroes like Troll Warlord.
Pick up a BKB too late, and you've lost.
Pick up a BKB too early, start using it, and late-game you won't have the duration time to make an impact.
I've started gauging about when I want to have a BKB and start using it. I try avoiding using it too much. But on a hero like Troll, and I've been rocking Vlad's as well. You can get your core items + BKB and go on a death roll.
Maybe I'm just whacky in the head meat.
No.1555
Get your BKB, and hold onto it the same way you'd hold onto a dust; pop it if you're sure it will win you a fight, or secure a kill (obviously must be worth more).
No.1559
If you're gonna get BKB, get it early, but know when to use it. Part of being a good player is knowing when and when not to use BKB.
Personally, I often don't use my BKBs enough when I buy them, so I'm actually TOO careful with using my charges.