I admit it:I love pad savers,because they are pretty,colorful and –supposedly –useful. Only recently I discovered that they can be a bit dangerous,thanks to my friend Domenico Bartolomeo,who repairs saxophones for living and for passion.
The fact is,pad savers should never,ever be left inside the horn,for several reasons. First,they keep humidity and therefore the prevent your pads from getting dry,which in turn make their life shorter. Second,they tend to leave dust inside the saxophone. Third,over time they tend to lose naps (hairs),which might prevent the pads from closing perfectly. I learned this lesson the hard way.
You can use a pad saver to clean the interior of your saxophone,of course. Just don’t leave them inside it. Used in this manner,I find pad savers especially useful with straight sopranos,whereas I prefer cleaning my alto by passing a cleaning cloth through the horn.
BTW,for the same reason I avoid –if possible,of course –to close the case of your sax immediately after practicing. I typically leave the case open for a few hours to let the humidity to go away,if necessary with a cloth over (not inside!) the saxophone to protect it from dust.