Yeah I usually buy multiple too, most of my WC comms have been hero modded so having multiple of those was a given hehe. I'm working on a B&W build as I don't have that version phaser ATM... taking a while though because I work a lot.The communicator battery is replaceable and easy to get at. If a lithium battery drains completely the cells can be damaged, so I try to charge my wand phasers and communicators up from time to time to keep the battery working as long as possible, I even charge the extra ones I bought that are still kept in the box in a closet.
yeah especially if you get the tricorder and want to complete the landing party set, it will cost you an arm and a leg.
I bought 4 phasers and 3 communicators and will probably get a couple tricorders too, I have not sold any for profit so far but I did give a set to my friend who is also a trekie and he displays them in his office.
I display a B&W SD Studios phaser and a stock phaser with an upgraded Stapleton Handel and one communicator, the others I keep hidden away in the box, incase anything happens to my display models.