I'd say yes, with the caveat that such aspects will expire after a time. You couldn't set up that ready for anything and invoke it the next day, for example. If your character has a nap, you'd have to re-establish it with another roll. Similarly, if your character is on midnight guard duty and going into his seventh straight hour with no breaks, the GM might call for an endurance roll to keep the aspect.
Basically, yes, but the rules do specify that these aspects are temporary, and the duration should depend on what makes sense to the group.