Can I test windows 7 repair usb even if windows is fine?

I successfully created a bootable windows 7 repair usb.
Please clarify me:
I rebooted my system via USB. windows repair window appeared. There were 5 options. I opted 'windows memory diagnostic' and it worked fine. There was an option named 'start up repair'. This option can be used if windows encountered problem as a result of which it isn't getting booted. My computer is having no such problem of start up but I wanted to check this option to get a 100 % confirmation that at times of need I can rely on my bootable usb. so, if I select this option (start up repair), I hope there shouldn't be any problem and this option would help me to enter my windows. Please note again, I want to simply test this option. (my windows is fine)

Bert Lance credited with this phrase...

If I were you I would not mess with Windows 7 at all as one mistake could _cost_ you...

I am only guessing, but........

Testing by doing an unnecessary _repair_ could _lock_you_out_ requiring a minimum of a password of some description to carry on...

Oh i was thinking I can verify the capability of my system recovery. I was feeling good to know that my work can never stop as windows repair usb is there with me.
It took quite a long time for me to make the bootable repair usb ready.