I have been using Bamboo for approximately three years.

We have been using Bamboo for almost a year.

I have been using Bamboo for a couple of years.

I have been using Bamboo for ten years.

I have been using Bamboo for almost eighteen months.

I have been using Bamboo for one and a half years.

We have been using Bamboo for three years.

I have been using Bamboo for approximately five years.

I have been using this solution for three months.

I've used it for five years.

3 years.

I have been using Bamboo for approximately eight months.

We have been using Bamboo for about 6 years now

These observations were part of a multi-department, one month evaluation where we decided to go with a different product in the end.

I have only used Bamboo at my current company and I've been there for a year now. 

I've used it for seven years,

Two to three years.

I've been using the solution for about a year.