I have been working with it for ten years.

I began using Case Foundation in 2008.

We've used the solution for a while. I've used it for eight years. 

We've been using the solution for 15 years now. 

I have been using this solution since 2016.

I have been working with IBM Case Foundation since 1998, just over 20 years ago.

I have been familiar with the IBM Case Foundation solution for three to four years.

I've been using the solution for almost 10 years.