Disclaimer: There isn't a sure way to know if you're going to be called.

That said, there are a few things you can look at. The first thing to look at is Call Me First. If you are not call me first, and there are people above you who are, check their eTrip to see if they have gotten any assignments. If not, you aren't going to be called unless they are. Also, look at the time and think logically. If you, or anyone, is called, the earliest you can leave the ground is 3 hours from that time (2 hours to drive in, 1 hour at the airport before departure). So if it's close to the end of your time block, probably not going to get called. Also, if there are other people coming onto reserve, that lessens your chances of getting called because they have more duty available. Finally, look at the weather. If it's a bright, beautiful sunny day, you can bet there's a lesser chance of flying than if it's lousy (like this past Friday...)

Of course, all of those are just strategies, and sometime scheduling surprises you. My advice is to always be ready, and if you are really paranoid about it, just take your things with you wherever you go. Then all you have to do is hop into a phone booth Superman-style and you'll be good to go!!