Limited time is all in the mind. I may be convinced more by limited money. Nevertheless, it is best to tell them to integrate into their daily routine their visit to their affiliate center in SFI. That way, they will be adapted to the site and become part of their daily routine activities to visit SFI site.
Another way is to let them internalize that it's just like daily going to attend a classes at school. Then let them compare the advantages they can get.