That's really up to you, but we'd recommend you upload as much data as possible. 2 years is normally a sensible minimum period when looking at Customer Lifetime Revenue and similar metrics, but you can absolutely upload a longer time period. We split our visual charts into 24 month segments (the last chart in each section will show less than 24 months if you don't upload a multiple of 24 months of data), so if you want to keep those neat, you may wish to upload data in a multiple of 24 months between the oldest and newest order.