Note the title of the thread
Actually you're partially correct. If you don't want to recycle them they can be reused but its important to note that the foam ear plugs form to the inside of your ear and the foam does have a memory, which can be very helpful if you've forgotten the notes to a specific song.
To reset the foam memory you'll need to pass the ear plugs to another band mate to use. Once inserted in a new set of ears the foam memory resets. You can expect most foam ear plugs to be good for about three sets of ears before the foam breaks down and begins to shrink.
The shrinkage factor (which can be significantly sped up with ice cold water) dictates that each subsequent set of ear canals the foam plugs are inserted in must be smaller than the previous ones. A logical progression of foam ear plug usage within the band would be the Bass Player first since they naturally have excellent listening skills and therefore larger more developed ear canals. The second user of the plugs should be the Drummer because over time the repeated banging has naturally caused his/her ear canals to shrink. The final user of the ear plugs should be the Guitarist since they are typically born with very small ear canals and are nearly incapable of listening to anything or anyone.
I hope this helps clear up the foam ear plug recycle vs reuse issue.