Roll my own...?

The big fear is the over-tightening, under-tightening. But if that's a real fear for you, then borrow a torque wrench off of someone.

+1

Since I bought my 2 torque wrenches a few years back -a 0-25 Nm and a 20-110 Nm - I always torque to exactly the recommended setting (or if the part comes with no instructions I Google around for a recommendation) - and it is fair to say that the days of rattling, squeaking, chainring bolts loosening, stuff breaking or simply dropping off are long gone (fingers crossed).

You certainly don't need a torque wrench, but they can make building bikes easier.