Agent Installation - One time or perpetual?

When adding computers in SOM and installing the agent immediately, there are some computers that will not have the agent installed because they are not currently connected to the network...specifically laptops. The question I have is does DC6 continually try to install the Agent to these computers, or is it a one time thing?

Reason I ask is that we have probably 50-75 laptops that I want included in patch updates, software rollouts etc, but if I have to keep trying to hit them manually to install the agent, that is going to be time consuming. Would love to have the agent installer check periodically those machines it was not originally able to contact and re-attempt (daily, weekly, something like that) until it does install.

Thx.