I have been a nurse at this hospital for 2006
When to use ‘for’ or 'since’ can be confusing for many students of English.
In the examples above, they have been used incorrectly.
For is used to say how long something has been happening: for 10 years, for some time, for 15 minutes, for a while.
Since is used to refer to when something started previously: since last night, since 2005, since birth, since last week, since arriving in Australia.
However, since is not used with periods of time: