Bubba was 1 1/2 when we got Sissy-she was very shy at first but came around quickly once she got comfortable. He helped housebreak her. They are best friends and keep each other company when I'm out or busy. The each have their own time for loving. Doubles the love with two. Yes, I take both out with me using a splitter and each has their own seat belt harness. 
The bad side-they are inseparable and cry and mope with out the other (he was depressed when she stayed at the vet for spaying). So they both go to the vet at the same time. AND he is a teaser-takes all the toys and bully sticks so the she starts crying and barking because she has nothing.
All in all it's great! Oh and by the way double the land mines in the yard
