It is often easier to ask for forgiveness than to ask for permission.
If it's a good idea, go ahead and do it. It is much easier to apologise than it is to get permission.
One accurate measurement is worth a thousand expert opinions.
At any given moment, there is always a line representing what your boss will believe. If you step over it, you will not get your budget. Go as close to that line as you can.
A ship in port is safe, but that's not what ships are built for.
You manage things, you lead people. We went overboard on management and forgot about leadership.