Made Tailor is having a promotion right now where they’re going to give away a custom shirt to one lucky winner. All you have to do is sign up and input your measurements. You can read about the contest here.
I normally wouldn’t post something like this, but frankly, I think this might be a good way to encourage people to get detailed measurements of their body. I’ve found it to be very useful to know even my most minor measurements, such as armhole and wrist size, for when I’m buying clothes online or getting things custom made.
Lastly, I strongly suggest that you go to a professional tailor for this. Use someone you really trust. I’ve found that non-professionals, and even “lower end” tailors, have a surprisingly difficult time getting accurate measurements. Get them once from a true professional, pay them $5-10 for the service, and keep the numbers on hand. They’ll come in handy sooner than you think.