The license says you can install the program on up to 5 computers that you own, which you can then use to prepare returns friends and family, as long as you don't charge for your services (which is a violation of the license and IRS regulations). The license does not say you can share the download with 4 other friends, although some people think that is what it means.
Either way, your license activation code is linked to your online account and you get a maximum of 5 activations.
Separately, the IRS limits each personal filer to 5 e-filed returns. This limit is enforceable by the IRS per user even if you buy a second copy of the program to get 5 extra activations. We don't know exactly how that is enforced, so we can't tell you if you can get around that limit by installing the program on different computers. If you need to file more than 5 returns, expect to print and mail them.
