more than a second license (quite expensive!), I would recommend to have a spare empty USB-eLicenser.
Besides the 25-hours license, which is good for 3 eight-hours working days, you can request a 30-days trial code without having to wait to have someone to reply your support enquiry.
[EDIT: Sorry, I noticed that SteveInChigago wrote the same after replying - cheers Steve]