It doesn't matter if you are on your own.  The same requirements mandated by the IRS' Security Summit apply to all tax software regardless of the number of users the subscriber may have.  Similarly, the software is required to log you out after a period of inactivity.

You don't have any choice and it's the same no matter which tax software you use.  It's all for the protection of your clients' data.

Your question implies that you may not be familiar with the obligations the IRS and FTC have imposed on tax practitioners, which include the establishment and on-going management of a data security plan.  If that is the case, you may like to refer to this pub for the relevant details:

https://www.irs.gov/pub/irs-pdf/p4557.pdf