I’m quite frugal and I will meld the old slivers onto the new bars. A penny saved is a penny saved, after all (not “earned”, please note). I have found that if the old sliver gets too small then it won’t bond to the new bar.
Am I the only one who saves the slivers to spread on my bagel after the shower?
My parents always used to stick the sliver on. I blindly followed suit for a while, but then realised that the sliver upsets the smoothness and symmetry of the new bar, so I now toss it out. Must not turn into parents… 
I stick them together, primarily because I really like a large bar of soap to wash with and replace the existing soap long before others would say it was too small. Soap is cheap and I could afford to throw it out, even the way I use it - but why be wasteful?
My last girlfriend somehow found this wrong and would always pry apart the soap and throw out the smallest part.
I use it until it’s as small as possible and then stick it between my butt cheeks and run in place until I have an ass that foams up like a mad dog.
I’m with ya on that, jammer.
Now here’s were I anticipate being handed my head, but isn’t soap soap? My wife buys the soap, and it is always white Dial. I’m sure she has her reasons - most likely due to the lack of odor (the soap’s, not mine). It never crossed my mind to ask her, “Hey, why don’t we try some Irish Spring/Dove/Caress/etc. this time.”
Ditto
Hell, yes. Granted, it won’t be as interesting as the zit thread or the cat abcess, but still. . .
Stick it to the new one, if there is anything left. I normally use it until it disintegrates.
It sounds like she’s not your girlfriend anymore, but that’s when you need to surreptitiously use the stuck together bars long enough that they can’t be split. Or better, use a knife to carve a single bar to look like two stuck together. 
Until I stopped using Ivory bar soap about 5 years ago, I had a dispenser jar into which I put the slivers and any other pieces (even whole small bars), added hot water, and screwed the pump-holding cap onto it. Viola-liquid soap in a pump dispenser, after the water dissolved the soap. Then, when that ran out, I started buying small prefilled dispensers of the antiseptic liquid soap and I buy the big jugs to refill them. I even take them to work and put them in the break room at the sink.
I saved up my slivers and built a remote island fortress. The erosion sucks though.
Not quite keyboard killing, but close.
I do what **NurseCarmen ** does.
I buy the other soaps, sure, but Dial is pretty solid, and lasts alot longer in my opinion. Ivory is so full of air bubbles that it floats in the bathtub, so half of the soap is air. If you drop Dial in the bathtub, it’s likely to break through the cast iron tub.
Dropped from great heights, Dial will break through the Earth’s crust. Dial is no longer sold in San Francisco.
I tuck the sliver under the bar in the soap holder that I take it to the gym with me. They consolidate when nobody is looking. I believe this is illegal in some states, both for moral reasons and because of the ass hairs that occasionally are trapped between sliver and bar and resurface later to frighten small children.
Regards,
Shodan