We got Brody at 14 months old, puppy sat a Shih Tzu a couple months later and when she went home after 4 days, Brody was so forlorn he'd just lie on the floor where her kennel had been. We knew he needed a friend, and found golden Mia, who is 6 days older than him and almost exactly the same size. Both were 17 months old when we took Brody to meet Mia to see if she was a good match. They were instant friends and are still today...7 1/2 months later.
It is a bit more work and expense, sure...you expect that. I cut bath time by putting each in his/her own side of my divided kitchen sink and bathing both at once. Sure, you'd have to get used to doing things a little different, and find your own timesavers, but bathing this way cuts my time in half...to just a little more than bathing Brody alone did. I assembly-line top knots, etc. whenever possible.
But the joy of having both to love...and how much they love you back, and watching them play and cuddle up together...of watching one get on the edge of a sofa or bed and play-defense against the other with all the fake growling, tails wagging, errr-ing, etc., of watching them beg and compete to be the first to get their clothes put on, of watching the other one complain to Daddy how they were passed over for first clothes on position, of watching both proudly displaying themselves to absolute strangers in a Lowe's shopping cart and exchanging silent but knowing Yorkie glances just because they know how wonderful they are...well, I wouldn't trade it for the whole world.
If you ever thought you might get a second one, perhaps you can make an arrangement to see if the two are right for each other. Your mind might get made for you.
Good luck.