I admit it, I have shown up to rehearsal without a mute a number of times because I left it at home. When I would forget to bring a mute to rehearsal, I would do one of two things: I would either try to hide the fact that I didn't have one by not saying anything about it, or I would try really hard to play soft during the 'muted' sections to blend in with the other musicians who were responsible enough to bring their own mutes.
Why would anybody forget to bring their mute? Why would they do such a thing?
There are two reasons I know of why anyone would take your mute off in the first place.
for one, sometimes the mute makes a rattle sound from the vibrations of the instrument, this of course is not good when playing solo music where the rattle is much more evident. The solution to get rid of the rattle is to, well, get rid of the mute! too bad some musicians forget to put it back on and just leave it sitting on the stand...
Secondly, when traveling with a removable neck bass, the mute usually comes off in the packing process, this must be done to allow the strings to fold nicely so they can fit in the slotted compartment in the removable neck travel case. Once the bass is packed in the travel case, bass players have a tendency to leave the mute behind on the floor.
How do I make sure no mute gets left behind?
The answer is to always carry two mutes instead of one. In the event that you 1) take off your mute before playing solo music to mitigate the risk of the mute rattling and causing extraneous noises, or 2) take the mute off before packing your bass in the travel case, you will always have an extra mute in your soft case as a form of backup should you lose the first one.
Imagine the piece of mind of always having a mute so you don't look foolish when its time to use it in rehearsal (let alone the concert). Imagine never having to worry about the 'evil eye' you get from all the other musicians that brought their mutes, when you yourself only showed up empty handed. If only you had two mutes instead of one, then you would not have to worry about this problem in the first place!
So what are you waiting for? get yourself two mutes today!
Below is a link to the mute I currently use.