Everyone talks about reusable bundles in symfony, but what about reusable services? Should they be easily reusable? Should they sometimes not? I was just thinking about moving some services outside of my bundle and put it directly into /src/services. For example I have a syntax parser that has been in the ForumBundle before, but now I want to use it in another bundle too. 

But then I thought, it might be also used in other projects, isn't that common because services should be less coupled because they are simpler than bundles?

Sometimes Iam even unsure if my service shouldn't become a complete bundle, how can I seperate the tasks of this two methods?