I've used the solution for four years.

We have been partners with Microsoft System Center for more than ten years.

We started using Microsoft System Center before they changed the name, so it has been more than 15 years. It was previously called Systems Management Server. 

I have six years of experience with Microsoft System Center.

I've been using the solution for seven years.

I have been using Microsoft System Center since 2018.

I've been using this solution for 10 years. 

We've been using this solution for ten years.

I've been using this solution for over 10 years. 

I have been using Microsoft for four years.