So I have successfully installed Ububtu alongside my Windows 8.1 so I am not sure what to do with the installation USB stick, can I delete the content and use it back as a normal USB Flash drive or do I need to keep it forever (sounds silly but also an option)?
It's always good to have a boot media around so you can repair any problems on the internal installation -- like a power failure causing disk corruption. Also, you might want to show a friend how Ubuntu works on their computer. There's no real need to keep it because you can always recreate it from Windows if needed.
Example: I've dedicated a 2GB stick I once received as a freebie to being a boot stick. It always contains the latest version of either Ubuntu or Mint on it, since I already have to 8GB sticks and don't really need it.– s3lphSep 28, 2014 at 17:31
Thanks it was clear answer, it's just that its 16GB one so I don't want it to just take all that space for Ubuntu, I think I will get a 2GB one for Ubuntu like you did, cheers. Sep 28, 2014 at 17:56