Should I use different content types or tags? I am working on my first Drupal site and I am worried about building things that will cause me trouble down the road.

The site is a move from a custom CMS to something more manageable. I didn't build the old CMS either. 

I have several items under labels like news, press release, announcements, etc. As I'm building out the content types I realize they could all be the same thing except they are considered something different by end users. 

Would something like this be a candidate for separate content types or one content type and I could tag each piece of content as "news" or "press release" etc. ? 

I'm hoping I can learn from someone else's mistake and get some hindsight on the topic.
I'd go for content types. That way you can easilly filter the content for the specific types when needed later.

It's easier to display all different content types at once, then to hide specific ones by their tags.