If you have never built wheels before, and don't have the experience to grossly estimate whether a wheel is under or overtensioned, then I implore you to buy a Park TM-1 tensionemter. It's $60. Seriously.

Ignore all the macho posts about using musical notes and other inaccurate and inconsistent methods to ascertain spoke tension - there's a tool specifically made to take the guesswork out

I will have to agree with Operator here that if you have little to no experience building wheels then a tension meter is an excellent and pretty much essential tool to have.

As to the old tried and true methods being "macho" or that there's guesswork involved when one is building standard wheels... then I have to disagree.

A friend was telling me that back in the sixties he went to Italy and while there received a hand built Bianchi (from the Bianchi factory) but was told that his wheels would be fabricated elsewhere.

He was taken to a small shop a little ways off where he mnet an elderly gentleman who, in the course of a few hours built up his wheels to perfection and these wheels remain perfect to this day.

He learned that the gentleman had been doing nothing but building wheels his entire life.

I am learning wheelbuilding right now. I can fix broken spokes and fix things good enough to get back home. Never had a spoke tensiometer. I still feel I can learn a lot here.

I have ridden some seriously out of true wheels for years and they always functioned well enough. Just to say it can be done. It seems to me riding an out of true wheel makes it worse over time? Fix it early and it stays good? This is the impression I am getting.

The other point is braking performance and out of true wheels. I was never really satisfied with the braking performance I was getting. But in those times I had other major brake maintenance issues which played a much bigger role in this. I can get some good braking performance from a little out of true wheels so I wonder how big an issue this is. Only briefly tried disc brakes. Btw the best brake performance Ive seen was from hydraulic brakes. I am getting very close to that with my regular brakes. Getting more expensive brake pads and comparing in the future. Anyone know much a little out true rim affect brake performance. Would be an interesting area of research.