Does Affluent collect historical data or only data from when I connect?

Affluent collects all historical data for any connected accounts. 

As soon as you add a new platform Affluent will start pulling in historical data.  Depending on the network and size of the account it can take anywhere between a couple of hours, to several days (or even longer in the case of ShareASale) before you have the entire account history. 

If you're connecting a SAS account, don't forget to check the programs API limit. For more information check out How to Connect ShareASale.