Yea I would just think that it would be harder to take them out. It's hard sometimes as it is now to take out Teddy and London together because they both pull on the leash so they get the leashes all tangled up and usually i just pick up London and have Teddy walk. If I had three how in the heck would I walk them..it would prob have to be at diff. times but oh well I'm willing to do that.
As for spening more money I would probably only spend more because I love buying clothes for them, especially matching outfits
But on food, toys, etc it would be the same because they share and I buy a big bag of food.