It's been more than five years now. I started using the product in 2016 - more than five years ago.

I've been using the solution for four years.

I have been using the solution for seven years.

I've been using the solution for about ten years. 

I've been using the product in a couple of my projects for six or seven years. 

I have been using this solution for a little more than two years.

I've been using SendGrid for four years.

We have been using the solution for one year.

For about two years now.

2 years

I've been using the SMTP API and Newsletter modules for one year and five months.