My personal philosophy is "better to have and not need than to need and not have." First of all, Jonathan Pollard is credited with providing the information which convinced the government to start the civilian gas mask program. Considering the price he has paid for that, I figure it must be very important.
When the government announced in 2007 that they were going to collect all the gas masks, I did not turn mine in. I waited until they announced that new ones were available in 2010 and then I traded my old one in for a new one. I've had my current one now for three years as well as every member of my family.
I pray to God that we will never have to use them, but "better to have and not need than to need and not have."
Since the booklets that accompany the kits are in Hebrew, I found the following video on Youtube which I like very much. It's a very nice presentation. You'll learn all you need to know from it.
One more thing. The government is telling people not to open the boxes. I imagine they are afraid that people will open the filters and that destroys the kit. You need to open the box and fit the mask to your head and practice a few times putting it on to be able to do it quickly. It's also good to get a feel for the mask in a less stressful situation because it can feel claustrophobic, sweaty, generally uncomfortable. But whatever you do, DO NOT OPEN THE FILTER. From the moment you open it, you only have a few hours before it loses all of its effectiveness. Save it for the critical moment when you know gas has landed in your area, God forbid it should ever happen!
So leave the seal on the filter. DO NOT ATTACH IT TO THE MASK. But, play around with the mask as much as you need to, so you will be able to put it on quickly and efficiently and effectively as the need arises.
PS: If you're wondering why the Israeli government only has enough masks for 40% of the population, search Youtube for "Israeli gas mask" and look at how many Americans are demonstrating the "Israeli" gas mask that they "bought."