I've been using the solution for more than 20 years at this point. It's been two decades. I've used it for quite a long time.

I have been working with IBM Informix for two years as a developer.

We have been using IBM Informix for five years.

I've been using the solution for 20 years or so. It's been about two decades. I've used it for a very long time.

I have been working with IBM Informix since 1986, it's been close to years.

I have been using this solution for three years now.

More than five years.

34 years as an end user, developer, and solution architect.

I've used this solution for eight years approximately. When I took over as a DBA, we were with version 9 (named Informix Workgroup version).

We have been using IBM Informix for seven years.

I've been using this solution for five years. 

We have been using IBM Informix for five years. 

I've been using the solution since 1995.