I have been using this solution for five to six years. We work with the latest version.

I've been using the solution for more than five years now.

I have been working with it for approximately eight years.

I have been working with this product for seven years.

I’ve been using the solution for approximately seven years.

We have used this solution for five years.

I've used the solution for about three or four months. 

We have been using the solution for fifteen years and are currently using version OS 7.

I've been using the solution for 11 years. 

We've used the solution for a while. We've likely used it for seven years or so. 

I have been working with this product for about 10 years.

I have been using this solution for about two years.

I have been using this product for the last five years.

I have been using this solution for more than five years. 

2 years.