Over time the high power draw of USB devices will reduce the ability of a USB chip to carry the power. As it is really an analog device carrying digital data, it is like any other analog device. It degrades with time and load.
The sleep issue, with Windows 7, has been there since Vista. It was improved with Windows 7, but still has many bugs in it.
If you can wrap your head around the following, it will serve you well.
Every time you boot your computer, Windows changes something. If you never reboot your computer, then Windows will change it based on time. At the end of every day, what you start with is not what you will finish with.