Hey Michael,
It depends on the script and the purpose. Some will post the whole script for long projects, so I'll just read less than a minute for those.
Other scripts are very short, so on those I may to several takes if it is warranted.
Small projects like "intro my podcast" may be a scenario where you should change the company name in the script, or watermark to be sure they don't use your audition as the final. This is normally only a concern on low-budget projects posted by individuals.
So, you can see the answer is very dependant on the job and copy posted...
Hope this helps,
Joe J Thomas
www.JoeActor.com